sivaq - university of colorado boulder · mission statement: augment the capabilities of the parrot...
TRANSCRIPT
SIVAQ Signal Integrity Verifying Autonomous Quadrotor
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
The Team
Brett Wiesman
Nick Brennan
Steve Gentile
Ross Hillery
Shane Meikle
Erin Overcash
Sean Rivera
Geoff Sissom
Matt Zhu
1
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Agenda
bull Objectives
bull Project description bull CONOPS
bull FBD
bull Requirements
bull Feasibility Studies
bull Further Testing
bull Questions
2
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Project Description
Mission Statement Augment the capabilities of the Parrot AR Drone 20 such that it flies autonomously with a predetermined
flight path records data relays data and detects and responds to GPS Radio Frequency Interference (RFI)
Mission Objectives
Establish a system that can detect GPS signal interference
Install extended range communication hardware on the drone
Develop software for communication data processing and piloting of the drone by selecting waypoints on a map at a ground station[1]
3
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Project Description
Highest Level of Success[2]
Autonomous quad rotor autopilot with
(a) GPS navigation system and signal integrity monitoring (b) ldquoReturn home capability
(c) Upgraded battery
(d) Custom housing and mechanical interface between electronics and vehicle (e) Extended-range 24GHz Wi-Fi communications device for transmission of
video data and last known position
(f) During 1 minute loiter SIVAQ will provide live video data such that the pilot can identify a red target 1 m2 in a 3600 m2 field
(g) 2D mapping of RFI area and photography to attempt to locate the RFI source (h) Interface for future additional sensor package
(i) Custom fuselage that improves efficiency while preserving center of gravity and structural integrity and ensures control algorithms will maintain stability New fuselage will house (a) (c) (e) and (h)
4
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Baseline Vehicle Hardware[3]
Memory DDcaR2 RAM
200 MHz clock
Wi-Fi Atheros AR61036 chipset
24 GHz Tx frequency
Forward facing camera
93
wide angle lens 720p
30fps recording speed
Motor Controller (x4)
USB port 400 Mbs
Downward facing camera
QVGA 64
diagonal lens
60 fps recording speed
Navboard
Altimeter Barometric pressure
sensor 10 Pa precision
Ultrasound 6 m precision
Accelerometer 3 axis
50 mg precision
Magnetometer 3 axis
6
precision
Motherboard
Motor (x4) Brushless
145 Watts 28500 RPM
Microball Berings
Nylatron Gears
IMU Invensense IMU-3000
Contains 3 axis gyro and input for 3-axis accelerometer
Microprocessor 32 bit ARM Cortex A8
1 GHz clock
Microprocessor 16 bit PIC
40 MHz clock
Battery Lithium Polymer
1000 mAh capacity
Solder Connection
Pin Connection
5
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Functional Black Diagram
Hard DataPower Connection
Wireless Data Connection
Developed for Project
Pre-Existing Hardware
Motherboard
Wi-Fi
USB port
AR Drone 20
Navigation
Software
Vehicle Kill
Command
Dynamic
Waypoints
Wi-Fi GUI
Battery Autonomous
Navigation
Software
RFI Detection
Software RFI Simulation
Vehicle Modifications
GPS Antenna
GPS Receiver
Storage Device
Electronics Package
Thermistor
USB HubPort
6
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
CONOPS
Loiter 1 minute and locate target using downward facing
camera Command
Destination and Waypoints for autonomous
travel
Begin flight with continuous signal
integrity monitoring and flight data transmission
Return home
Downlink and store flight data
in real time
Travel towards estimated
target location
7
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
CONOPS ndash Scenario 2
Continuous signal monitoring and
data transmission detection
Command Destination and Waypoints for autonomous
travel
Downlink and store flight data
in real time
Immediate powerful RFI detected Lose
Communication link with ground station
Abort mission disable GPS and
attempt to return home inertially
Immediate large radius RFI is
enabled
8
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
False GPS sphere of influence
CONOPS ndash Scenario 3
Command Destination and Waypoints for autonomous
travel False Signal Detected
Viable communication link with ground station
Attempt to map sphere of
influence or locate source of RFI
Continuous signal monitoring and
data transmission detection
Downlink and store flight data
in real time
9
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Functional Requirements[1]
REFERENCE Description
1QUADFR1 SIVAQ shall travel autonomously via predetermined waypoints while maintaining pseudo range accuracy of 78
meters (TBR) at 95 confidence level
1QUADFR2
SIVAQ shall monitor GPS information integrity and detect radio frequency interference Signal shall be
considered compromised if AGC level is greater than three from nominal AGC level
1QUADFR3 SIVAQ shall create map RFI zone of influence
1QUADFR4 SIVAQ shall return to ground station once mission is completed or at 30 (TBR) battery life remaining
1QUADFR5 SIVAQ shall be able to fly to a target location within a 3km radius area capture video data for 1 min then return
home
1QUADFR6 Finalized SIVAQ cost shall be less than $750 (TBR) in components
1QUADFR7 SIVAQ shall be operational in open terrain and in conditions of ideal weather (no precipitation and no wind)
1QUADFR8 SIVAQ shall be equipped with an extended range 24 GHz Wi-Fi two-way communications device
1QUADFR9 During 1 minute loiter SIVAQ will provide live video data such that the pilot can identify a red target 1 m2 in a
10000 m2 field
1GRNFR1 A GUI will allow the user to select waypoints and specify the vehicles mission Additionally the user will be able
to alter waypoints during flight
1GRNFR2 The command center must be able to receive and display data sent from the vehicle for processing
10
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Baseline Design Selections[1]
Subsystem Design Selection
RFI detection Automatic Gain Control signal monitoring
Mass and Power Structural modification and high capacity Li-Ion battery
Communications 24 GHz Wi-Fi antenna modification
Mission Data USB flash storage and Wi-Fi 80211n streaming
Control Software AutoPylot written in MATLAB
Navigation method GPS based waypoint navigation
GUI Software NASA WorldWind mapping software and Java Swing
11
CDD Design Solutions
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Feasibility Studies
Aspects of the project analyzed for feasibility
1 How will the vehicle detect and simulate RFI
2 Is 6 km range (3km out and back) possible given mass and power considerations
3 Can the vehicle maintain communication link with the ground station over 3km distance
4 Can vehicle accommodate required data transfer and storage rates
5 Does MATLAB have an acceptable response time for control software
6 Is waypoint style navigation possible with selected software
12
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
Automatic Gain Control
bull Automatic Gain Control (AGC) is an adaptive circuit which dynamically adjusts incoming signal gains to match the level requirement of downstream electronics[4]
bull AGC is low complexity and is intrinsic in all multi-bit GPS receivers
bull AGC is not part of NMEA message but some civilian GPS receivers include it in the digital output
bull GPS RFI can be detected by monitoring the output of the AGC circuitry bull A boosted GPS signal causes the
AGC to drop
13
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
bull A study conducted in Sweden[4] using a GPS RFI device showed that AGC can be used to accurately detect GPS RFI bull AGC output is monitored for a
drop below a predetermined threshold
bull This proves the feasibility of the AGC detection method
14
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AGC Signal Characterization
bull AGC levels are subject to noise from surroundings[3]
bull Refinements can be made to AGC measurements by accounting for thermal noise and other signals present in the frequency band
bull Noise can be characterized for the specific GPS module and flight conditions to properly detect active RFI
15 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - Noise Characterization
bull Ground and Flight models of the GPS modules will be bench tested and data will be logged using a data acquisition system
bull Tests will be run both on and off the UAV platform bull On-platform tests will be run with the vehicle off on and in
controlled flight
bull Results from this test will allow for the characterization of noise in the GPS signal for various conditions
Thermistor
16 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - L1 Injection
bull An L1 GPS signal simulator will be fed through a variable gain amplifier and injected into the GPS RF stream simulating a malicious RFI source
bull A data acquisition system will be used to monitor and log the AGC signal from the GPS module
bull This ground test will be used to characterize AGC response to an amplified signal in the L1 band and determine the appropriate threshold at which AGC will accurately denote GPS RFI
17
Thermistor
RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Waypoint-based RFI Simulation bull To implement RFI in flight (currently illegal) data from RFI ground tests are
used to create a software simulation which mimics the results of actual RFI on the AGC signal in the GPS modulersquos digital output
bull GPS waypoints are used to define the perimeter of the simulated RFI zone which when breached will result in simulated RFI manipulating the digital AGC signal
Nav Software
RFI Software
Thermistor
18 RFI Simulation Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Customer Requirement ARDrone 20 shall fly 3 km from launch point loiter for 60 seconds then return 3 km to takeoff point ARDrone 20 Capabilities Manufacturer Claim 36 km max range (Cruise Speed 5 ms Flight Time 12 minutes) User Claim 225 km max range (Chuck Rossetti claims only Wi-Fi modifications) Drivers for Range Requirement bull Commercially available radio frequency interference devices have extremely
variable areas of influence (up to 6km) but the typical RFI device ldquozone of influencerdquo extends 2 to 500 meters from signal source
bull Extended range improves functionality of ARDrone 20 enables ability to map ldquozonerdquo of GPS corruption
bull Range improvement enables increased flexibility in future missions (Customer Request)
19
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AR Drone Mass Budget
Required Components
Component Mass [g] Percent of Stock Mass []
Stock Outdoor Vehicle
424 10000
GPS ReceiverAntenna
20 472
4000 mAh Battery (Dynamite Speed Pack Silver)
225 4693
Polarized Antenna 11 259
USB 1 024
Magnetic Compass 014 003
Total Mass 68114 16065
Component Mass [g] Percent of Stock Mass []
Outdoor Hull
32 952
1000 mAh Battery
101 2405
Stickers 10 238
USB Port 5 119
Camera Arm
5 119
Total Mass 153 3833
Unrequired Components
Final Mass 52814 [g] 12456 [ of stock]
20
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
The Team
Brett Wiesman
Nick Brennan
Steve Gentile
Ross Hillery
Shane Meikle
Erin Overcash
Sean Rivera
Geoff Sissom
Matt Zhu
1
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Agenda
bull Objectives
bull Project description bull CONOPS
bull FBD
bull Requirements
bull Feasibility Studies
bull Further Testing
bull Questions
2
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Project Description
Mission Statement Augment the capabilities of the Parrot AR Drone 20 such that it flies autonomously with a predetermined
flight path records data relays data and detects and responds to GPS Radio Frequency Interference (RFI)
Mission Objectives
Establish a system that can detect GPS signal interference
Install extended range communication hardware on the drone
Develop software for communication data processing and piloting of the drone by selecting waypoints on a map at a ground station[1]
3
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Project Description
Highest Level of Success[2]
Autonomous quad rotor autopilot with
(a) GPS navigation system and signal integrity monitoring (b) ldquoReturn home capability
(c) Upgraded battery
(d) Custom housing and mechanical interface between electronics and vehicle (e) Extended-range 24GHz Wi-Fi communications device for transmission of
video data and last known position
(f) During 1 minute loiter SIVAQ will provide live video data such that the pilot can identify a red target 1 m2 in a 3600 m2 field
(g) 2D mapping of RFI area and photography to attempt to locate the RFI source (h) Interface for future additional sensor package
(i) Custom fuselage that improves efficiency while preserving center of gravity and structural integrity and ensures control algorithms will maintain stability New fuselage will house (a) (c) (e) and (h)
4
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Baseline Vehicle Hardware[3]
Memory DDcaR2 RAM
200 MHz clock
Wi-Fi Atheros AR61036 chipset
24 GHz Tx frequency
Forward facing camera
93
wide angle lens 720p
30fps recording speed
Motor Controller (x4)
USB port 400 Mbs
Downward facing camera
QVGA 64
diagonal lens
60 fps recording speed
Navboard
Altimeter Barometric pressure
sensor 10 Pa precision
Ultrasound 6 m precision
Accelerometer 3 axis
50 mg precision
Magnetometer 3 axis
6
precision
Motherboard
Motor (x4) Brushless
145 Watts 28500 RPM
Microball Berings
Nylatron Gears
IMU Invensense IMU-3000
Contains 3 axis gyro and input for 3-axis accelerometer
Microprocessor 32 bit ARM Cortex A8
1 GHz clock
Microprocessor 16 bit PIC
40 MHz clock
Battery Lithium Polymer
1000 mAh capacity
Solder Connection
Pin Connection
5
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Functional Black Diagram
Hard DataPower Connection
Wireless Data Connection
Developed for Project
Pre-Existing Hardware
Motherboard
Wi-Fi
USB port
AR Drone 20
Navigation
Software
Vehicle Kill
Command
Dynamic
Waypoints
Wi-Fi GUI
Battery Autonomous
Navigation
Software
RFI Detection
Software RFI Simulation
Vehicle Modifications
GPS Antenna
GPS Receiver
Storage Device
Electronics Package
Thermistor
USB HubPort
6
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
CONOPS
Loiter 1 minute and locate target using downward facing
camera Command
Destination and Waypoints for autonomous
travel
Begin flight with continuous signal
integrity monitoring and flight data transmission
Return home
Downlink and store flight data
in real time
Travel towards estimated
target location
7
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
CONOPS ndash Scenario 2
Continuous signal monitoring and
data transmission detection
Command Destination and Waypoints for autonomous
travel
Downlink and store flight data
in real time
Immediate powerful RFI detected Lose
Communication link with ground station
Abort mission disable GPS and
attempt to return home inertially
Immediate large radius RFI is
enabled
8
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
False GPS sphere of influence
CONOPS ndash Scenario 3
Command Destination and Waypoints for autonomous
travel False Signal Detected
Viable communication link with ground station
Attempt to map sphere of
influence or locate source of RFI
Continuous signal monitoring and
data transmission detection
Downlink and store flight data
in real time
9
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Functional Requirements[1]
REFERENCE Description
1QUADFR1 SIVAQ shall travel autonomously via predetermined waypoints while maintaining pseudo range accuracy of 78
meters (TBR) at 95 confidence level
1QUADFR2
SIVAQ shall monitor GPS information integrity and detect radio frequency interference Signal shall be
considered compromised if AGC level is greater than three from nominal AGC level
1QUADFR3 SIVAQ shall create map RFI zone of influence
1QUADFR4 SIVAQ shall return to ground station once mission is completed or at 30 (TBR) battery life remaining
1QUADFR5 SIVAQ shall be able to fly to a target location within a 3km radius area capture video data for 1 min then return
home
1QUADFR6 Finalized SIVAQ cost shall be less than $750 (TBR) in components
1QUADFR7 SIVAQ shall be operational in open terrain and in conditions of ideal weather (no precipitation and no wind)
1QUADFR8 SIVAQ shall be equipped with an extended range 24 GHz Wi-Fi two-way communications device
1QUADFR9 During 1 minute loiter SIVAQ will provide live video data such that the pilot can identify a red target 1 m2 in a
10000 m2 field
1GRNFR1 A GUI will allow the user to select waypoints and specify the vehicles mission Additionally the user will be able
to alter waypoints during flight
1GRNFR2 The command center must be able to receive and display data sent from the vehicle for processing
10
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Baseline Design Selections[1]
Subsystem Design Selection
RFI detection Automatic Gain Control signal monitoring
Mass and Power Structural modification and high capacity Li-Ion battery
Communications 24 GHz Wi-Fi antenna modification
Mission Data USB flash storage and Wi-Fi 80211n streaming
Control Software AutoPylot written in MATLAB
Navigation method GPS based waypoint navigation
GUI Software NASA WorldWind mapping software and Java Swing
11
CDD Design Solutions
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Feasibility Studies
Aspects of the project analyzed for feasibility
1 How will the vehicle detect and simulate RFI
2 Is 6 km range (3km out and back) possible given mass and power considerations
3 Can the vehicle maintain communication link with the ground station over 3km distance
4 Can vehicle accommodate required data transfer and storage rates
5 Does MATLAB have an acceptable response time for control software
6 Is waypoint style navigation possible with selected software
12
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
Automatic Gain Control
bull Automatic Gain Control (AGC) is an adaptive circuit which dynamically adjusts incoming signal gains to match the level requirement of downstream electronics[4]
bull AGC is low complexity and is intrinsic in all multi-bit GPS receivers
bull AGC is not part of NMEA message but some civilian GPS receivers include it in the digital output
bull GPS RFI can be detected by monitoring the output of the AGC circuitry bull A boosted GPS signal causes the
AGC to drop
13
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
bull A study conducted in Sweden[4] using a GPS RFI device showed that AGC can be used to accurately detect GPS RFI bull AGC output is monitored for a
drop below a predetermined threshold
bull This proves the feasibility of the AGC detection method
14
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AGC Signal Characterization
bull AGC levels are subject to noise from surroundings[3]
bull Refinements can be made to AGC measurements by accounting for thermal noise and other signals present in the frequency band
bull Noise can be characterized for the specific GPS module and flight conditions to properly detect active RFI
15 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - Noise Characterization
bull Ground and Flight models of the GPS modules will be bench tested and data will be logged using a data acquisition system
bull Tests will be run both on and off the UAV platform bull On-platform tests will be run with the vehicle off on and in
controlled flight
bull Results from this test will allow for the characterization of noise in the GPS signal for various conditions
Thermistor
16 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - L1 Injection
bull An L1 GPS signal simulator will be fed through a variable gain amplifier and injected into the GPS RF stream simulating a malicious RFI source
bull A data acquisition system will be used to monitor and log the AGC signal from the GPS module
bull This ground test will be used to characterize AGC response to an amplified signal in the L1 band and determine the appropriate threshold at which AGC will accurately denote GPS RFI
17
Thermistor
RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Waypoint-based RFI Simulation bull To implement RFI in flight (currently illegal) data from RFI ground tests are
used to create a software simulation which mimics the results of actual RFI on the AGC signal in the GPS modulersquos digital output
bull GPS waypoints are used to define the perimeter of the simulated RFI zone which when breached will result in simulated RFI manipulating the digital AGC signal
Nav Software
RFI Software
Thermistor
18 RFI Simulation Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Customer Requirement ARDrone 20 shall fly 3 km from launch point loiter for 60 seconds then return 3 km to takeoff point ARDrone 20 Capabilities Manufacturer Claim 36 km max range (Cruise Speed 5 ms Flight Time 12 minutes) User Claim 225 km max range (Chuck Rossetti claims only Wi-Fi modifications) Drivers for Range Requirement bull Commercially available radio frequency interference devices have extremely
variable areas of influence (up to 6km) but the typical RFI device ldquozone of influencerdquo extends 2 to 500 meters from signal source
bull Extended range improves functionality of ARDrone 20 enables ability to map ldquozonerdquo of GPS corruption
bull Range improvement enables increased flexibility in future missions (Customer Request)
19
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AR Drone Mass Budget
Required Components
Component Mass [g] Percent of Stock Mass []
Stock Outdoor Vehicle
424 10000
GPS ReceiverAntenna
20 472
4000 mAh Battery (Dynamite Speed Pack Silver)
225 4693
Polarized Antenna 11 259
USB 1 024
Magnetic Compass 014 003
Total Mass 68114 16065
Component Mass [g] Percent of Stock Mass []
Outdoor Hull
32 952
1000 mAh Battery
101 2405
Stickers 10 238
USB Port 5 119
Camera Arm
5 119
Total Mass 153 3833
Unrequired Components
Final Mass 52814 [g] 12456 [ of stock]
20
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Agenda
bull Objectives
bull Project description bull CONOPS
bull FBD
bull Requirements
bull Feasibility Studies
bull Further Testing
bull Questions
2
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Project Description
Mission Statement Augment the capabilities of the Parrot AR Drone 20 such that it flies autonomously with a predetermined
flight path records data relays data and detects and responds to GPS Radio Frequency Interference (RFI)
Mission Objectives
Establish a system that can detect GPS signal interference
Install extended range communication hardware on the drone
Develop software for communication data processing and piloting of the drone by selecting waypoints on a map at a ground station[1]
3
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Project Description
Highest Level of Success[2]
Autonomous quad rotor autopilot with
(a) GPS navigation system and signal integrity monitoring (b) ldquoReturn home capability
(c) Upgraded battery
(d) Custom housing and mechanical interface between electronics and vehicle (e) Extended-range 24GHz Wi-Fi communications device for transmission of
video data and last known position
(f) During 1 minute loiter SIVAQ will provide live video data such that the pilot can identify a red target 1 m2 in a 3600 m2 field
(g) 2D mapping of RFI area and photography to attempt to locate the RFI source (h) Interface for future additional sensor package
(i) Custom fuselage that improves efficiency while preserving center of gravity and structural integrity and ensures control algorithms will maintain stability New fuselage will house (a) (c) (e) and (h)
4
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Baseline Vehicle Hardware[3]
Memory DDcaR2 RAM
200 MHz clock
Wi-Fi Atheros AR61036 chipset
24 GHz Tx frequency
Forward facing camera
93
wide angle lens 720p
30fps recording speed
Motor Controller (x4)
USB port 400 Mbs
Downward facing camera
QVGA 64
diagonal lens
60 fps recording speed
Navboard
Altimeter Barometric pressure
sensor 10 Pa precision
Ultrasound 6 m precision
Accelerometer 3 axis
50 mg precision
Magnetometer 3 axis
6
precision
Motherboard
Motor (x4) Brushless
145 Watts 28500 RPM
Microball Berings
Nylatron Gears
IMU Invensense IMU-3000
Contains 3 axis gyro and input for 3-axis accelerometer
Microprocessor 32 bit ARM Cortex A8
1 GHz clock
Microprocessor 16 bit PIC
40 MHz clock
Battery Lithium Polymer
1000 mAh capacity
Solder Connection
Pin Connection
5
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Functional Black Diagram
Hard DataPower Connection
Wireless Data Connection
Developed for Project
Pre-Existing Hardware
Motherboard
Wi-Fi
USB port
AR Drone 20
Navigation
Software
Vehicle Kill
Command
Dynamic
Waypoints
Wi-Fi GUI
Battery Autonomous
Navigation
Software
RFI Detection
Software RFI Simulation
Vehicle Modifications
GPS Antenna
GPS Receiver
Storage Device
Electronics Package
Thermistor
USB HubPort
6
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
CONOPS
Loiter 1 minute and locate target using downward facing
camera Command
Destination and Waypoints for autonomous
travel
Begin flight with continuous signal
integrity monitoring and flight data transmission
Return home
Downlink and store flight data
in real time
Travel towards estimated
target location
7
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
CONOPS ndash Scenario 2
Continuous signal monitoring and
data transmission detection
Command Destination and Waypoints for autonomous
travel
Downlink and store flight data
in real time
Immediate powerful RFI detected Lose
Communication link with ground station
Abort mission disable GPS and
attempt to return home inertially
Immediate large radius RFI is
enabled
8
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
False GPS sphere of influence
CONOPS ndash Scenario 3
Command Destination and Waypoints for autonomous
travel False Signal Detected
Viable communication link with ground station
Attempt to map sphere of
influence or locate source of RFI
Continuous signal monitoring and
data transmission detection
Downlink and store flight data
in real time
9
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Functional Requirements[1]
REFERENCE Description
1QUADFR1 SIVAQ shall travel autonomously via predetermined waypoints while maintaining pseudo range accuracy of 78
meters (TBR) at 95 confidence level
1QUADFR2
SIVAQ shall monitor GPS information integrity and detect radio frequency interference Signal shall be
considered compromised if AGC level is greater than three from nominal AGC level
1QUADFR3 SIVAQ shall create map RFI zone of influence
1QUADFR4 SIVAQ shall return to ground station once mission is completed or at 30 (TBR) battery life remaining
1QUADFR5 SIVAQ shall be able to fly to a target location within a 3km radius area capture video data for 1 min then return
home
1QUADFR6 Finalized SIVAQ cost shall be less than $750 (TBR) in components
1QUADFR7 SIVAQ shall be operational in open terrain and in conditions of ideal weather (no precipitation and no wind)
1QUADFR8 SIVAQ shall be equipped with an extended range 24 GHz Wi-Fi two-way communications device
1QUADFR9 During 1 minute loiter SIVAQ will provide live video data such that the pilot can identify a red target 1 m2 in a
10000 m2 field
1GRNFR1 A GUI will allow the user to select waypoints and specify the vehicles mission Additionally the user will be able
to alter waypoints during flight
1GRNFR2 The command center must be able to receive and display data sent from the vehicle for processing
10
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Baseline Design Selections[1]
Subsystem Design Selection
RFI detection Automatic Gain Control signal monitoring
Mass and Power Structural modification and high capacity Li-Ion battery
Communications 24 GHz Wi-Fi antenna modification
Mission Data USB flash storage and Wi-Fi 80211n streaming
Control Software AutoPylot written in MATLAB
Navigation method GPS based waypoint navigation
GUI Software NASA WorldWind mapping software and Java Swing
11
CDD Design Solutions
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Feasibility Studies
Aspects of the project analyzed for feasibility
1 How will the vehicle detect and simulate RFI
2 Is 6 km range (3km out and back) possible given mass and power considerations
3 Can the vehicle maintain communication link with the ground station over 3km distance
4 Can vehicle accommodate required data transfer and storage rates
5 Does MATLAB have an acceptable response time for control software
6 Is waypoint style navigation possible with selected software
12
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
Automatic Gain Control
bull Automatic Gain Control (AGC) is an adaptive circuit which dynamically adjusts incoming signal gains to match the level requirement of downstream electronics[4]
bull AGC is low complexity and is intrinsic in all multi-bit GPS receivers
bull AGC is not part of NMEA message but some civilian GPS receivers include it in the digital output
bull GPS RFI can be detected by monitoring the output of the AGC circuitry bull A boosted GPS signal causes the
AGC to drop
13
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
bull A study conducted in Sweden[4] using a GPS RFI device showed that AGC can be used to accurately detect GPS RFI bull AGC output is monitored for a
drop below a predetermined threshold
bull This proves the feasibility of the AGC detection method
14
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AGC Signal Characterization
bull AGC levels are subject to noise from surroundings[3]
bull Refinements can be made to AGC measurements by accounting for thermal noise and other signals present in the frequency band
bull Noise can be characterized for the specific GPS module and flight conditions to properly detect active RFI
15 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - Noise Characterization
bull Ground and Flight models of the GPS modules will be bench tested and data will be logged using a data acquisition system
bull Tests will be run both on and off the UAV platform bull On-platform tests will be run with the vehicle off on and in
controlled flight
bull Results from this test will allow for the characterization of noise in the GPS signal for various conditions
Thermistor
16 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - L1 Injection
bull An L1 GPS signal simulator will be fed through a variable gain amplifier and injected into the GPS RF stream simulating a malicious RFI source
bull A data acquisition system will be used to monitor and log the AGC signal from the GPS module
bull This ground test will be used to characterize AGC response to an amplified signal in the L1 band and determine the appropriate threshold at which AGC will accurately denote GPS RFI
17
Thermistor
RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Waypoint-based RFI Simulation bull To implement RFI in flight (currently illegal) data from RFI ground tests are
used to create a software simulation which mimics the results of actual RFI on the AGC signal in the GPS modulersquos digital output
bull GPS waypoints are used to define the perimeter of the simulated RFI zone which when breached will result in simulated RFI manipulating the digital AGC signal
Nav Software
RFI Software
Thermistor
18 RFI Simulation Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Customer Requirement ARDrone 20 shall fly 3 km from launch point loiter for 60 seconds then return 3 km to takeoff point ARDrone 20 Capabilities Manufacturer Claim 36 km max range (Cruise Speed 5 ms Flight Time 12 minutes) User Claim 225 km max range (Chuck Rossetti claims only Wi-Fi modifications) Drivers for Range Requirement bull Commercially available radio frequency interference devices have extremely
variable areas of influence (up to 6km) but the typical RFI device ldquozone of influencerdquo extends 2 to 500 meters from signal source
bull Extended range improves functionality of ARDrone 20 enables ability to map ldquozonerdquo of GPS corruption
bull Range improvement enables increased flexibility in future missions (Customer Request)
19
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AR Drone Mass Budget
Required Components
Component Mass [g] Percent of Stock Mass []
Stock Outdoor Vehicle
424 10000
GPS ReceiverAntenna
20 472
4000 mAh Battery (Dynamite Speed Pack Silver)
225 4693
Polarized Antenna 11 259
USB 1 024
Magnetic Compass 014 003
Total Mass 68114 16065
Component Mass [g] Percent of Stock Mass []
Outdoor Hull
32 952
1000 mAh Battery
101 2405
Stickers 10 238
USB Port 5 119
Camera Arm
5 119
Total Mass 153 3833
Unrequired Components
Final Mass 52814 [g] 12456 [ of stock]
20
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Project Description
Mission Statement Augment the capabilities of the Parrot AR Drone 20 such that it flies autonomously with a predetermined
flight path records data relays data and detects and responds to GPS Radio Frequency Interference (RFI)
Mission Objectives
Establish a system that can detect GPS signal interference
Install extended range communication hardware on the drone
Develop software for communication data processing and piloting of the drone by selecting waypoints on a map at a ground station[1]
3
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Project Description
Highest Level of Success[2]
Autonomous quad rotor autopilot with
(a) GPS navigation system and signal integrity monitoring (b) ldquoReturn home capability
(c) Upgraded battery
(d) Custom housing and mechanical interface between electronics and vehicle (e) Extended-range 24GHz Wi-Fi communications device for transmission of
video data and last known position
(f) During 1 minute loiter SIVAQ will provide live video data such that the pilot can identify a red target 1 m2 in a 3600 m2 field
(g) 2D mapping of RFI area and photography to attempt to locate the RFI source (h) Interface for future additional sensor package
(i) Custom fuselage that improves efficiency while preserving center of gravity and structural integrity and ensures control algorithms will maintain stability New fuselage will house (a) (c) (e) and (h)
4
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Baseline Vehicle Hardware[3]
Memory DDcaR2 RAM
200 MHz clock
Wi-Fi Atheros AR61036 chipset
24 GHz Tx frequency
Forward facing camera
93
wide angle lens 720p
30fps recording speed
Motor Controller (x4)
USB port 400 Mbs
Downward facing camera
QVGA 64
diagonal lens
60 fps recording speed
Navboard
Altimeter Barometric pressure
sensor 10 Pa precision
Ultrasound 6 m precision
Accelerometer 3 axis
50 mg precision
Magnetometer 3 axis
6
precision
Motherboard
Motor (x4) Brushless
145 Watts 28500 RPM
Microball Berings
Nylatron Gears
IMU Invensense IMU-3000
Contains 3 axis gyro and input for 3-axis accelerometer
Microprocessor 32 bit ARM Cortex A8
1 GHz clock
Microprocessor 16 bit PIC
40 MHz clock
Battery Lithium Polymer
1000 mAh capacity
Solder Connection
Pin Connection
5
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Functional Black Diagram
Hard DataPower Connection
Wireless Data Connection
Developed for Project
Pre-Existing Hardware
Motherboard
Wi-Fi
USB port
AR Drone 20
Navigation
Software
Vehicle Kill
Command
Dynamic
Waypoints
Wi-Fi GUI
Battery Autonomous
Navigation
Software
RFI Detection
Software RFI Simulation
Vehicle Modifications
GPS Antenna
GPS Receiver
Storage Device
Electronics Package
Thermistor
USB HubPort
6
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
CONOPS
Loiter 1 minute and locate target using downward facing
camera Command
Destination and Waypoints for autonomous
travel
Begin flight with continuous signal
integrity monitoring and flight data transmission
Return home
Downlink and store flight data
in real time
Travel towards estimated
target location
7
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
CONOPS ndash Scenario 2
Continuous signal monitoring and
data transmission detection
Command Destination and Waypoints for autonomous
travel
Downlink and store flight data
in real time
Immediate powerful RFI detected Lose
Communication link with ground station
Abort mission disable GPS and
attempt to return home inertially
Immediate large radius RFI is
enabled
8
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
False GPS sphere of influence
CONOPS ndash Scenario 3
Command Destination and Waypoints for autonomous
travel False Signal Detected
Viable communication link with ground station
Attempt to map sphere of
influence or locate source of RFI
Continuous signal monitoring and
data transmission detection
Downlink and store flight data
in real time
9
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Functional Requirements[1]
REFERENCE Description
1QUADFR1 SIVAQ shall travel autonomously via predetermined waypoints while maintaining pseudo range accuracy of 78
meters (TBR) at 95 confidence level
1QUADFR2
SIVAQ shall monitor GPS information integrity and detect radio frequency interference Signal shall be
considered compromised if AGC level is greater than three from nominal AGC level
1QUADFR3 SIVAQ shall create map RFI zone of influence
1QUADFR4 SIVAQ shall return to ground station once mission is completed or at 30 (TBR) battery life remaining
1QUADFR5 SIVAQ shall be able to fly to a target location within a 3km radius area capture video data for 1 min then return
home
1QUADFR6 Finalized SIVAQ cost shall be less than $750 (TBR) in components
1QUADFR7 SIVAQ shall be operational in open terrain and in conditions of ideal weather (no precipitation and no wind)
1QUADFR8 SIVAQ shall be equipped with an extended range 24 GHz Wi-Fi two-way communications device
1QUADFR9 During 1 minute loiter SIVAQ will provide live video data such that the pilot can identify a red target 1 m2 in a
10000 m2 field
1GRNFR1 A GUI will allow the user to select waypoints and specify the vehicles mission Additionally the user will be able
to alter waypoints during flight
1GRNFR2 The command center must be able to receive and display data sent from the vehicle for processing
10
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Baseline Design Selections[1]
Subsystem Design Selection
RFI detection Automatic Gain Control signal monitoring
Mass and Power Structural modification and high capacity Li-Ion battery
Communications 24 GHz Wi-Fi antenna modification
Mission Data USB flash storage and Wi-Fi 80211n streaming
Control Software AutoPylot written in MATLAB
Navigation method GPS based waypoint navigation
GUI Software NASA WorldWind mapping software and Java Swing
11
CDD Design Solutions
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Feasibility Studies
Aspects of the project analyzed for feasibility
1 How will the vehicle detect and simulate RFI
2 Is 6 km range (3km out and back) possible given mass and power considerations
3 Can the vehicle maintain communication link with the ground station over 3km distance
4 Can vehicle accommodate required data transfer and storage rates
5 Does MATLAB have an acceptable response time for control software
6 Is waypoint style navigation possible with selected software
12
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
Automatic Gain Control
bull Automatic Gain Control (AGC) is an adaptive circuit which dynamically adjusts incoming signal gains to match the level requirement of downstream electronics[4]
bull AGC is low complexity and is intrinsic in all multi-bit GPS receivers
bull AGC is not part of NMEA message but some civilian GPS receivers include it in the digital output
bull GPS RFI can be detected by monitoring the output of the AGC circuitry bull A boosted GPS signal causes the
AGC to drop
13
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
bull A study conducted in Sweden[4] using a GPS RFI device showed that AGC can be used to accurately detect GPS RFI bull AGC output is monitored for a
drop below a predetermined threshold
bull This proves the feasibility of the AGC detection method
14
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AGC Signal Characterization
bull AGC levels are subject to noise from surroundings[3]
bull Refinements can be made to AGC measurements by accounting for thermal noise and other signals present in the frequency band
bull Noise can be characterized for the specific GPS module and flight conditions to properly detect active RFI
15 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - Noise Characterization
bull Ground and Flight models of the GPS modules will be bench tested and data will be logged using a data acquisition system
bull Tests will be run both on and off the UAV platform bull On-platform tests will be run with the vehicle off on and in
controlled flight
bull Results from this test will allow for the characterization of noise in the GPS signal for various conditions
Thermistor
16 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - L1 Injection
bull An L1 GPS signal simulator will be fed through a variable gain amplifier and injected into the GPS RF stream simulating a malicious RFI source
bull A data acquisition system will be used to monitor and log the AGC signal from the GPS module
bull This ground test will be used to characterize AGC response to an amplified signal in the L1 band and determine the appropriate threshold at which AGC will accurately denote GPS RFI
17
Thermistor
RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Waypoint-based RFI Simulation bull To implement RFI in flight (currently illegal) data from RFI ground tests are
used to create a software simulation which mimics the results of actual RFI on the AGC signal in the GPS modulersquos digital output
bull GPS waypoints are used to define the perimeter of the simulated RFI zone which when breached will result in simulated RFI manipulating the digital AGC signal
Nav Software
RFI Software
Thermistor
18 RFI Simulation Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Customer Requirement ARDrone 20 shall fly 3 km from launch point loiter for 60 seconds then return 3 km to takeoff point ARDrone 20 Capabilities Manufacturer Claim 36 km max range (Cruise Speed 5 ms Flight Time 12 minutes) User Claim 225 km max range (Chuck Rossetti claims only Wi-Fi modifications) Drivers for Range Requirement bull Commercially available radio frequency interference devices have extremely
variable areas of influence (up to 6km) but the typical RFI device ldquozone of influencerdquo extends 2 to 500 meters from signal source
bull Extended range improves functionality of ARDrone 20 enables ability to map ldquozonerdquo of GPS corruption
bull Range improvement enables increased flexibility in future missions (Customer Request)
19
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AR Drone Mass Budget
Required Components
Component Mass [g] Percent of Stock Mass []
Stock Outdoor Vehicle
424 10000
GPS ReceiverAntenna
20 472
4000 mAh Battery (Dynamite Speed Pack Silver)
225 4693
Polarized Antenna 11 259
USB 1 024
Magnetic Compass 014 003
Total Mass 68114 16065
Component Mass [g] Percent of Stock Mass []
Outdoor Hull
32 952
1000 mAh Battery
101 2405
Stickers 10 238
USB Port 5 119
Camera Arm
5 119
Total Mass 153 3833
Unrequired Components
Final Mass 52814 [g] 12456 [ of stock]
20
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Project Description
Highest Level of Success[2]
Autonomous quad rotor autopilot with
(a) GPS navigation system and signal integrity monitoring (b) ldquoReturn home capability
(c) Upgraded battery
(d) Custom housing and mechanical interface between electronics and vehicle (e) Extended-range 24GHz Wi-Fi communications device for transmission of
video data and last known position
(f) During 1 minute loiter SIVAQ will provide live video data such that the pilot can identify a red target 1 m2 in a 3600 m2 field
(g) 2D mapping of RFI area and photography to attempt to locate the RFI source (h) Interface for future additional sensor package
(i) Custom fuselage that improves efficiency while preserving center of gravity and structural integrity and ensures control algorithms will maintain stability New fuselage will house (a) (c) (e) and (h)
4
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Baseline Vehicle Hardware[3]
Memory DDcaR2 RAM
200 MHz clock
Wi-Fi Atheros AR61036 chipset
24 GHz Tx frequency
Forward facing camera
93
wide angle lens 720p
30fps recording speed
Motor Controller (x4)
USB port 400 Mbs
Downward facing camera
QVGA 64
diagonal lens
60 fps recording speed
Navboard
Altimeter Barometric pressure
sensor 10 Pa precision
Ultrasound 6 m precision
Accelerometer 3 axis
50 mg precision
Magnetometer 3 axis
6
precision
Motherboard
Motor (x4) Brushless
145 Watts 28500 RPM
Microball Berings
Nylatron Gears
IMU Invensense IMU-3000
Contains 3 axis gyro and input for 3-axis accelerometer
Microprocessor 32 bit ARM Cortex A8
1 GHz clock
Microprocessor 16 bit PIC
40 MHz clock
Battery Lithium Polymer
1000 mAh capacity
Solder Connection
Pin Connection
5
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Functional Black Diagram
Hard DataPower Connection
Wireless Data Connection
Developed for Project
Pre-Existing Hardware
Motherboard
Wi-Fi
USB port
AR Drone 20
Navigation
Software
Vehicle Kill
Command
Dynamic
Waypoints
Wi-Fi GUI
Battery Autonomous
Navigation
Software
RFI Detection
Software RFI Simulation
Vehicle Modifications
GPS Antenna
GPS Receiver
Storage Device
Electronics Package
Thermistor
USB HubPort
6
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
CONOPS
Loiter 1 minute and locate target using downward facing
camera Command
Destination and Waypoints for autonomous
travel
Begin flight with continuous signal
integrity monitoring and flight data transmission
Return home
Downlink and store flight data
in real time
Travel towards estimated
target location
7
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
CONOPS ndash Scenario 2
Continuous signal monitoring and
data transmission detection
Command Destination and Waypoints for autonomous
travel
Downlink and store flight data
in real time
Immediate powerful RFI detected Lose
Communication link with ground station
Abort mission disable GPS and
attempt to return home inertially
Immediate large radius RFI is
enabled
8
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
False GPS sphere of influence
CONOPS ndash Scenario 3
Command Destination and Waypoints for autonomous
travel False Signal Detected
Viable communication link with ground station
Attempt to map sphere of
influence or locate source of RFI
Continuous signal monitoring and
data transmission detection
Downlink and store flight data
in real time
9
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Functional Requirements[1]
REFERENCE Description
1QUADFR1 SIVAQ shall travel autonomously via predetermined waypoints while maintaining pseudo range accuracy of 78
meters (TBR) at 95 confidence level
1QUADFR2
SIVAQ shall monitor GPS information integrity and detect radio frequency interference Signal shall be
considered compromised if AGC level is greater than three from nominal AGC level
1QUADFR3 SIVAQ shall create map RFI zone of influence
1QUADFR4 SIVAQ shall return to ground station once mission is completed or at 30 (TBR) battery life remaining
1QUADFR5 SIVAQ shall be able to fly to a target location within a 3km radius area capture video data for 1 min then return
home
1QUADFR6 Finalized SIVAQ cost shall be less than $750 (TBR) in components
1QUADFR7 SIVAQ shall be operational in open terrain and in conditions of ideal weather (no precipitation and no wind)
1QUADFR8 SIVAQ shall be equipped with an extended range 24 GHz Wi-Fi two-way communications device
1QUADFR9 During 1 minute loiter SIVAQ will provide live video data such that the pilot can identify a red target 1 m2 in a
10000 m2 field
1GRNFR1 A GUI will allow the user to select waypoints and specify the vehicles mission Additionally the user will be able
to alter waypoints during flight
1GRNFR2 The command center must be able to receive and display data sent from the vehicle for processing
10
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Baseline Design Selections[1]
Subsystem Design Selection
RFI detection Automatic Gain Control signal monitoring
Mass and Power Structural modification and high capacity Li-Ion battery
Communications 24 GHz Wi-Fi antenna modification
Mission Data USB flash storage and Wi-Fi 80211n streaming
Control Software AutoPylot written in MATLAB
Navigation method GPS based waypoint navigation
GUI Software NASA WorldWind mapping software and Java Swing
11
CDD Design Solutions
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Feasibility Studies
Aspects of the project analyzed for feasibility
1 How will the vehicle detect and simulate RFI
2 Is 6 km range (3km out and back) possible given mass and power considerations
3 Can the vehicle maintain communication link with the ground station over 3km distance
4 Can vehicle accommodate required data transfer and storage rates
5 Does MATLAB have an acceptable response time for control software
6 Is waypoint style navigation possible with selected software
12
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
Automatic Gain Control
bull Automatic Gain Control (AGC) is an adaptive circuit which dynamically adjusts incoming signal gains to match the level requirement of downstream electronics[4]
bull AGC is low complexity and is intrinsic in all multi-bit GPS receivers
bull AGC is not part of NMEA message but some civilian GPS receivers include it in the digital output
bull GPS RFI can be detected by monitoring the output of the AGC circuitry bull A boosted GPS signal causes the
AGC to drop
13
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
bull A study conducted in Sweden[4] using a GPS RFI device showed that AGC can be used to accurately detect GPS RFI bull AGC output is monitored for a
drop below a predetermined threshold
bull This proves the feasibility of the AGC detection method
14
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AGC Signal Characterization
bull AGC levels are subject to noise from surroundings[3]
bull Refinements can be made to AGC measurements by accounting for thermal noise and other signals present in the frequency band
bull Noise can be characterized for the specific GPS module and flight conditions to properly detect active RFI
15 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - Noise Characterization
bull Ground and Flight models of the GPS modules will be bench tested and data will be logged using a data acquisition system
bull Tests will be run both on and off the UAV platform bull On-platform tests will be run with the vehicle off on and in
controlled flight
bull Results from this test will allow for the characterization of noise in the GPS signal for various conditions
Thermistor
16 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - L1 Injection
bull An L1 GPS signal simulator will be fed through a variable gain amplifier and injected into the GPS RF stream simulating a malicious RFI source
bull A data acquisition system will be used to monitor and log the AGC signal from the GPS module
bull This ground test will be used to characterize AGC response to an amplified signal in the L1 band and determine the appropriate threshold at which AGC will accurately denote GPS RFI
17
Thermistor
RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Waypoint-based RFI Simulation bull To implement RFI in flight (currently illegal) data from RFI ground tests are
used to create a software simulation which mimics the results of actual RFI on the AGC signal in the GPS modulersquos digital output
bull GPS waypoints are used to define the perimeter of the simulated RFI zone which when breached will result in simulated RFI manipulating the digital AGC signal
Nav Software
RFI Software
Thermistor
18 RFI Simulation Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Customer Requirement ARDrone 20 shall fly 3 km from launch point loiter for 60 seconds then return 3 km to takeoff point ARDrone 20 Capabilities Manufacturer Claim 36 km max range (Cruise Speed 5 ms Flight Time 12 minutes) User Claim 225 km max range (Chuck Rossetti claims only Wi-Fi modifications) Drivers for Range Requirement bull Commercially available radio frequency interference devices have extremely
variable areas of influence (up to 6km) but the typical RFI device ldquozone of influencerdquo extends 2 to 500 meters from signal source
bull Extended range improves functionality of ARDrone 20 enables ability to map ldquozonerdquo of GPS corruption
bull Range improvement enables increased flexibility in future missions (Customer Request)
19
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AR Drone Mass Budget
Required Components
Component Mass [g] Percent of Stock Mass []
Stock Outdoor Vehicle
424 10000
GPS ReceiverAntenna
20 472
4000 mAh Battery (Dynamite Speed Pack Silver)
225 4693
Polarized Antenna 11 259
USB 1 024
Magnetic Compass 014 003
Total Mass 68114 16065
Component Mass [g] Percent of Stock Mass []
Outdoor Hull
32 952
1000 mAh Battery
101 2405
Stickers 10 238
USB Port 5 119
Camera Arm
5 119
Total Mass 153 3833
Unrequired Components
Final Mass 52814 [g] 12456 [ of stock]
20
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Baseline Vehicle Hardware[3]
Memory DDcaR2 RAM
200 MHz clock
Wi-Fi Atheros AR61036 chipset
24 GHz Tx frequency
Forward facing camera
93
wide angle lens 720p
30fps recording speed
Motor Controller (x4)
USB port 400 Mbs
Downward facing camera
QVGA 64
diagonal lens
60 fps recording speed
Navboard
Altimeter Barometric pressure
sensor 10 Pa precision
Ultrasound 6 m precision
Accelerometer 3 axis
50 mg precision
Magnetometer 3 axis
6
precision
Motherboard
Motor (x4) Brushless
145 Watts 28500 RPM
Microball Berings
Nylatron Gears
IMU Invensense IMU-3000
Contains 3 axis gyro and input for 3-axis accelerometer
Microprocessor 32 bit ARM Cortex A8
1 GHz clock
Microprocessor 16 bit PIC
40 MHz clock
Battery Lithium Polymer
1000 mAh capacity
Solder Connection
Pin Connection
5
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Functional Black Diagram
Hard DataPower Connection
Wireless Data Connection
Developed for Project
Pre-Existing Hardware
Motherboard
Wi-Fi
USB port
AR Drone 20
Navigation
Software
Vehicle Kill
Command
Dynamic
Waypoints
Wi-Fi GUI
Battery Autonomous
Navigation
Software
RFI Detection
Software RFI Simulation
Vehicle Modifications
GPS Antenna
GPS Receiver
Storage Device
Electronics Package
Thermistor
USB HubPort
6
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
CONOPS
Loiter 1 minute and locate target using downward facing
camera Command
Destination and Waypoints for autonomous
travel
Begin flight with continuous signal
integrity monitoring and flight data transmission
Return home
Downlink and store flight data
in real time
Travel towards estimated
target location
7
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
CONOPS ndash Scenario 2
Continuous signal monitoring and
data transmission detection
Command Destination and Waypoints for autonomous
travel
Downlink and store flight data
in real time
Immediate powerful RFI detected Lose
Communication link with ground station
Abort mission disable GPS and
attempt to return home inertially
Immediate large radius RFI is
enabled
8
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
False GPS sphere of influence
CONOPS ndash Scenario 3
Command Destination and Waypoints for autonomous
travel False Signal Detected
Viable communication link with ground station
Attempt to map sphere of
influence or locate source of RFI
Continuous signal monitoring and
data transmission detection
Downlink and store flight data
in real time
9
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Functional Requirements[1]
REFERENCE Description
1QUADFR1 SIVAQ shall travel autonomously via predetermined waypoints while maintaining pseudo range accuracy of 78
meters (TBR) at 95 confidence level
1QUADFR2
SIVAQ shall monitor GPS information integrity and detect radio frequency interference Signal shall be
considered compromised if AGC level is greater than three from nominal AGC level
1QUADFR3 SIVAQ shall create map RFI zone of influence
1QUADFR4 SIVAQ shall return to ground station once mission is completed or at 30 (TBR) battery life remaining
1QUADFR5 SIVAQ shall be able to fly to a target location within a 3km radius area capture video data for 1 min then return
home
1QUADFR6 Finalized SIVAQ cost shall be less than $750 (TBR) in components
1QUADFR7 SIVAQ shall be operational in open terrain and in conditions of ideal weather (no precipitation and no wind)
1QUADFR8 SIVAQ shall be equipped with an extended range 24 GHz Wi-Fi two-way communications device
1QUADFR9 During 1 minute loiter SIVAQ will provide live video data such that the pilot can identify a red target 1 m2 in a
10000 m2 field
1GRNFR1 A GUI will allow the user to select waypoints and specify the vehicles mission Additionally the user will be able
to alter waypoints during flight
1GRNFR2 The command center must be able to receive and display data sent from the vehicle for processing
10
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Baseline Design Selections[1]
Subsystem Design Selection
RFI detection Automatic Gain Control signal monitoring
Mass and Power Structural modification and high capacity Li-Ion battery
Communications 24 GHz Wi-Fi antenna modification
Mission Data USB flash storage and Wi-Fi 80211n streaming
Control Software AutoPylot written in MATLAB
Navigation method GPS based waypoint navigation
GUI Software NASA WorldWind mapping software and Java Swing
11
CDD Design Solutions
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Feasibility Studies
Aspects of the project analyzed for feasibility
1 How will the vehicle detect and simulate RFI
2 Is 6 km range (3km out and back) possible given mass and power considerations
3 Can the vehicle maintain communication link with the ground station over 3km distance
4 Can vehicle accommodate required data transfer and storage rates
5 Does MATLAB have an acceptable response time for control software
6 Is waypoint style navigation possible with selected software
12
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
Automatic Gain Control
bull Automatic Gain Control (AGC) is an adaptive circuit which dynamically adjusts incoming signal gains to match the level requirement of downstream electronics[4]
bull AGC is low complexity and is intrinsic in all multi-bit GPS receivers
bull AGC is not part of NMEA message but some civilian GPS receivers include it in the digital output
bull GPS RFI can be detected by monitoring the output of the AGC circuitry bull A boosted GPS signal causes the
AGC to drop
13
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
bull A study conducted in Sweden[4] using a GPS RFI device showed that AGC can be used to accurately detect GPS RFI bull AGC output is monitored for a
drop below a predetermined threshold
bull This proves the feasibility of the AGC detection method
14
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AGC Signal Characterization
bull AGC levels are subject to noise from surroundings[3]
bull Refinements can be made to AGC measurements by accounting for thermal noise and other signals present in the frequency band
bull Noise can be characterized for the specific GPS module and flight conditions to properly detect active RFI
15 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - Noise Characterization
bull Ground and Flight models of the GPS modules will be bench tested and data will be logged using a data acquisition system
bull Tests will be run both on and off the UAV platform bull On-platform tests will be run with the vehicle off on and in
controlled flight
bull Results from this test will allow for the characterization of noise in the GPS signal for various conditions
Thermistor
16 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - L1 Injection
bull An L1 GPS signal simulator will be fed through a variable gain amplifier and injected into the GPS RF stream simulating a malicious RFI source
bull A data acquisition system will be used to monitor and log the AGC signal from the GPS module
bull This ground test will be used to characterize AGC response to an amplified signal in the L1 band and determine the appropriate threshold at which AGC will accurately denote GPS RFI
17
Thermistor
RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Waypoint-based RFI Simulation bull To implement RFI in flight (currently illegal) data from RFI ground tests are
used to create a software simulation which mimics the results of actual RFI on the AGC signal in the GPS modulersquos digital output
bull GPS waypoints are used to define the perimeter of the simulated RFI zone which when breached will result in simulated RFI manipulating the digital AGC signal
Nav Software
RFI Software
Thermistor
18 RFI Simulation Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Customer Requirement ARDrone 20 shall fly 3 km from launch point loiter for 60 seconds then return 3 km to takeoff point ARDrone 20 Capabilities Manufacturer Claim 36 km max range (Cruise Speed 5 ms Flight Time 12 minutes) User Claim 225 km max range (Chuck Rossetti claims only Wi-Fi modifications) Drivers for Range Requirement bull Commercially available radio frequency interference devices have extremely
variable areas of influence (up to 6km) but the typical RFI device ldquozone of influencerdquo extends 2 to 500 meters from signal source
bull Extended range improves functionality of ARDrone 20 enables ability to map ldquozonerdquo of GPS corruption
bull Range improvement enables increased flexibility in future missions (Customer Request)
19
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AR Drone Mass Budget
Required Components
Component Mass [g] Percent of Stock Mass []
Stock Outdoor Vehicle
424 10000
GPS ReceiverAntenna
20 472
4000 mAh Battery (Dynamite Speed Pack Silver)
225 4693
Polarized Antenna 11 259
USB 1 024
Magnetic Compass 014 003
Total Mass 68114 16065
Component Mass [g] Percent of Stock Mass []
Outdoor Hull
32 952
1000 mAh Battery
101 2405
Stickers 10 238
USB Port 5 119
Camera Arm
5 119
Total Mass 153 3833
Unrequired Components
Final Mass 52814 [g] 12456 [ of stock]
20
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Functional Black Diagram
Hard DataPower Connection
Wireless Data Connection
Developed for Project
Pre-Existing Hardware
Motherboard
Wi-Fi
USB port
AR Drone 20
Navigation
Software
Vehicle Kill
Command
Dynamic
Waypoints
Wi-Fi GUI
Battery Autonomous
Navigation
Software
RFI Detection
Software RFI Simulation
Vehicle Modifications
GPS Antenna
GPS Receiver
Storage Device
Electronics Package
Thermistor
USB HubPort
6
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
CONOPS
Loiter 1 minute and locate target using downward facing
camera Command
Destination and Waypoints for autonomous
travel
Begin flight with continuous signal
integrity monitoring and flight data transmission
Return home
Downlink and store flight data
in real time
Travel towards estimated
target location
7
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
CONOPS ndash Scenario 2
Continuous signal monitoring and
data transmission detection
Command Destination and Waypoints for autonomous
travel
Downlink and store flight data
in real time
Immediate powerful RFI detected Lose
Communication link with ground station
Abort mission disable GPS and
attempt to return home inertially
Immediate large radius RFI is
enabled
8
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
False GPS sphere of influence
CONOPS ndash Scenario 3
Command Destination and Waypoints for autonomous
travel False Signal Detected
Viable communication link with ground station
Attempt to map sphere of
influence or locate source of RFI
Continuous signal monitoring and
data transmission detection
Downlink and store flight data
in real time
9
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Functional Requirements[1]
REFERENCE Description
1QUADFR1 SIVAQ shall travel autonomously via predetermined waypoints while maintaining pseudo range accuracy of 78
meters (TBR) at 95 confidence level
1QUADFR2
SIVAQ shall monitor GPS information integrity and detect radio frequency interference Signal shall be
considered compromised if AGC level is greater than three from nominal AGC level
1QUADFR3 SIVAQ shall create map RFI zone of influence
1QUADFR4 SIVAQ shall return to ground station once mission is completed or at 30 (TBR) battery life remaining
1QUADFR5 SIVAQ shall be able to fly to a target location within a 3km radius area capture video data for 1 min then return
home
1QUADFR6 Finalized SIVAQ cost shall be less than $750 (TBR) in components
1QUADFR7 SIVAQ shall be operational in open terrain and in conditions of ideal weather (no precipitation and no wind)
1QUADFR8 SIVAQ shall be equipped with an extended range 24 GHz Wi-Fi two-way communications device
1QUADFR9 During 1 minute loiter SIVAQ will provide live video data such that the pilot can identify a red target 1 m2 in a
10000 m2 field
1GRNFR1 A GUI will allow the user to select waypoints and specify the vehicles mission Additionally the user will be able
to alter waypoints during flight
1GRNFR2 The command center must be able to receive and display data sent from the vehicle for processing
10
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Baseline Design Selections[1]
Subsystem Design Selection
RFI detection Automatic Gain Control signal monitoring
Mass and Power Structural modification and high capacity Li-Ion battery
Communications 24 GHz Wi-Fi antenna modification
Mission Data USB flash storage and Wi-Fi 80211n streaming
Control Software AutoPylot written in MATLAB
Navigation method GPS based waypoint navigation
GUI Software NASA WorldWind mapping software and Java Swing
11
CDD Design Solutions
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Feasibility Studies
Aspects of the project analyzed for feasibility
1 How will the vehicle detect and simulate RFI
2 Is 6 km range (3km out and back) possible given mass and power considerations
3 Can the vehicle maintain communication link with the ground station over 3km distance
4 Can vehicle accommodate required data transfer and storage rates
5 Does MATLAB have an acceptable response time for control software
6 Is waypoint style navigation possible with selected software
12
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
Automatic Gain Control
bull Automatic Gain Control (AGC) is an adaptive circuit which dynamically adjusts incoming signal gains to match the level requirement of downstream electronics[4]
bull AGC is low complexity and is intrinsic in all multi-bit GPS receivers
bull AGC is not part of NMEA message but some civilian GPS receivers include it in the digital output
bull GPS RFI can be detected by monitoring the output of the AGC circuitry bull A boosted GPS signal causes the
AGC to drop
13
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
bull A study conducted in Sweden[4] using a GPS RFI device showed that AGC can be used to accurately detect GPS RFI bull AGC output is monitored for a
drop below a predetermined threshold
bull This proves the feasibility of the AGC detection method
14
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AGC Signal Characterization
bull AGC levels are subject to noise from surroundings[3]
bull Refinements can be made to AGC measurements by accounting for thermal noise and other signals present in the frequency band
bull Noise can be characterized for the specific GPS module and flight conditions to properly detect active RFI
15 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - Noise Characterization
bull Ground and Flight models of the GPS modules will be bench tested and data will be logged using a data acquisition system
bull Tests will be run both on and off the UAV platform bull On-platform tests will be run with the vehicle off on and in
controlled flight
bull Results from this test will allow for the characterization of noise in the GPS signal for various conditions
Thermistor
16 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - L1 Injection
bull An L1 GPS signal simulator will be fed through a variable gain amplifier and injected into the GPS RF stream simulating a malicious RFI source
bull A data acquisition system will be used to monitor and log the AGC signal from the GPS module
bull This ground test will be used to characterize AGC response to an amplified signal in the L1 band and determine the appropriate threshold at which AGC will accurately denote GPS RFI
17
Thermistor
RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Waypoint-based RFI Simulation bull To implement RFI in flight (currently illegal) data from RFI ground tests are
used to create a software simulation which mimics the results of actual RFI on the AGC signal in the GPS modulersquos digital output
bull GPS waypoints are used to define the perimeter of the simulated RFI zone which when breached will result in simulated RFI manipulating the digital AGC signal
Nav Software
RFI Software
Thermistor
18 RFI Simulation Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Customer Requirement ARDrone 20 shall fly 3 km from launch point loiter for 60 seconds then return 3 km to takeoff point ARDrone 20 Capabilities Manufacturer Claim 36 km max range (Cruise Speed 5 ms Flight Time 12 minutes) User Claim 225 km max range (Chuck Rossetti claims only Wi-Fi modifications) Drivers for Range Requirement bull Commercially available radio frequency interference devices have extremely
variable areas of influence (up to 6km) but the typical RFI device ldquozone of influencerdquo extends 2 to 500 meters from signal source
bull Extended range improves functionality of ARDrone 20 enables ability to map ldquozonerdquo of GPS corruption
bull Range improvement enables increased flexibility in future missions (Customer Request)
19
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AR Drone Mass Budget
Required Components
Component Mass [g] Percent of Stock Mass []
Stock Outdoor Vehicle
424 10000
GPS ReceiverAntenna
20 472
4000 mAh Battery (Dynamite Speed Pack Silver)
225 4693
Polarized Antenna 11 259
USB 1 024
Magnetic Compass 014 003
Total Mass 68114 16065
Component Mass [g] Percent of Stock Mass []
Outdoor Hull
32 952
1000 mAh Battery
101 2405
Stickers 10 238
USB Port 5 119
Camera Arm
5 119
Total Mass 153 3833
Unrequired Components
Final Mass 52814 [g] 12456 [ of stock]
20
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
CONOPS
Loiter 1 minute and locate target using downward facing
camera Command
Destination and Waypoints for autonomous
travel
Begin flight with continuous signal
integrity monitoring and flight data transmission
Return home
Downlink and store flight data
in real time
Travel towards estimated
target location
7
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
CONOPS ndash Scenario 2
Continuous signal monitoring and
data transmission detection
Command Destination and Waypoints for autonomous
travel
Downlink and store flight data
in real time
Immediate powerful RFI detected Lose
Communication link with ground station
Abort mission disable GPS and
attempt to return home inertially
Immediate large radius RFI is
enabled
8
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
False GPS sphere of influence
CONOPS ndash Scenario 3
Command Destination and Waypoints for autonomous
travel False Signal Detected
Viable communication link with ground station
Attempt to map sphere of
influence or locate source of RFI
Continuous signal monitoring and
data transmission detection
Downlink and store flight data
in real time
9
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Functional Requirements[1]
REFERENCE Description
1QUADFR1 SIVAQ shall travel autonomously via predetermined waypoints while maintaining pseudo range accuracy of 78
meters (TBR) at 95 confidence level
1QUADFR2
SIVAQ shall monitor GPS information integrity and detect radio frequency interference Signal shall be
considered compromised if AGC level is greater than three from nominal AGC level
1QUADFR3 SIVAQ shall create map RFI zone of influence
1QUADFR4 SIVAQ shall return to ground station once mission is completed or at 30 (TBR) battery life remaining
1QUADFR5 SIVAQ shall be able to fly to a target location within a 3km radius area capture video data for 1 min then return
home
1QUADFR6 Finalized SIVAQ cost shall be less than $750 (TBR) in components
1QUADFR7 SIVAQ shall be operational in open terrain and in conditions of ideal weather (no precipitation and no wind)
1QUADFR8 SIVAQ shall be equipped with an extended range 24 GHz Wi-Fi two-way communications device
1QUADFR9 During 1 minute loiter SIVAQ will provide live video data such that the pilot can identify a red target 1 m2 in a
10000 m2 field
1GRNFR1 A GUI will allow the user to select waypoints and specify the vehicles mission Additionally the user will be able
to alter waypoints during flight
1GRNFR2 The command center must be able to receive and display data sent from the vehicle for processing
10
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Baseline Design Selections[1]
Subsystem Design Selection
RFI detection Automatic Gain Control signal monitoring
Mass and Power Structural modification and high capacity Li-Ion battery
Communications 24 GHz Wi-Fi antenna modification
Mission Data USB flash storage and Wi-Fi 80211n streaming
Control Software AutoPylot written in MATLAB
Navigation method GPS based waypoint navigation
GUI Software NASA WorldWind mapping software and Java Swing
11
CDD Design Solutions
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Feasibility Studies
Aspects of the project analyzed for feasibility
1 How will the vehicle detect and simulate RFI
2 Is 6 km range (3km out and back) possible given mass and power considerations
3 Can the vehicle maintain communication link with the ground station over 3km distance
4 Can vehicle accommodate required data transfer and storage rates
5 Does MATLAB have an acceptable response time for control software
6 Is waypoint style navigation possible with selected software
12
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
Automatic Gain Control
bull Automatic Gain Control (AGC) is an adaptive circuit which dynamically adjusts incoming signal gains to match the level requirement of downstream electronics[4]
bull AGC is low complexity and is intrinsic in all multi-bit GPS receivers
bull AGC is not part of NMEA message but some civilian GPS receivers include it in the digital output
bull GPS RFI can be detected by monitoring the output of the AGC circuitry bull A boosted GPS signal causes the
AGC to drop
13
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
bull A study conducted in Sweden[4] using a GPS RFI device showed that AGC can be used to accurately detect GPS RFI bull AGC output is monitored for a
drop below a predetermined threshold
bull This proves the feasibility of the AGC detection method
14
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AGC Signal Characterization
bull AGC levels are subject to noise from surroundings[3]
bull Refinements can be made to AGC measurements by accounting for thermal noise and other signals present in the frequency band
bull Noise can be characterized for the specific GPS module and flight conditions to properly detect active RFI
15 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - Noise Characterization
bull Ground and Flight models of the GPS modules will be bench tested and data will be logged using a data acquisition system
bull Tests will be run both on and off the UAV platform bull On-platform tests will be run with the vehicle off on and in
controlled flight
bull Results from this test will allow for the characterization of noise in the GPS signal for various conditions
Thermistor
16 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - L1 Injection
bull An L1 GPS signal simulator will be fed through a variable gain amplifier and injected into the GPS RF stream simulating a malicious RFI source
bull A data acquisition system will be used to monitor and log the AGC signal from the GPS module
bull This ground test will be used to characterize AGC response to an amplified signal in the L1 band and determine the appropriate threshold at which AGC will accurately denote GPS RFI
17
Thermistor
RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Waypoint-based RFI Simulation bull To implement RFI in flight (currently illegal) data from RFI ground tests are
used to create a software simulation which mimics the results of actual RFI on the AGC signal in the GPS modulersquos digital output
bull GPS waypoints are used to define the perimeter of the simulated RFI zone which when breached will result in simulated RFI manipulating the digital AGC signal
Nav Software
RFI Software
Thermistor
18 RFI Simulation Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Customer Requirement ARDrone 20 shall fly 3 km from launch point loiter for 60 seconds then return 3 km to takeoff point ARDrone 20 Capabilities Manufacturer Claim 36 km max range (Cruise Speed 5 ms Flight Time 12 minutes) User Claim 225 km max range (Chuck Rossetti claims only Wi-Fi modifications) Drivers for Range Requirement bull Commercially available radio frequency interference devices have extremely
variable areas of influence (up to 6km) but the typical RFI device ldquozone of influencerdquo extends 2 to 500 meters from signal source
bull Extended range improves functionality of ARDrone 20 enables ability to map ldquozonerdquo of GPS corruption
bull Range improvement enables increased flexibility in future missions (Customer Request)
19
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AR Drone Mass Budget
Required Components
Component Mass [g] Percent of Stock Mass []
Stock Outdoor Vehicle
424 10000
GPS ReceiverAntenna
20 472
4000 mAh Battery (Dynamite Speed Pack Silver)
225 4693
Polarized Antenna 11 259
USB 1 024
Magnetic Compass 014 003
Total Mass 68114 16065
Component Mass [g] Percent of Stock Mass []
Outdoor Hull
32 952
1000 mAh Battery
101 2405
Stickers 10 238
USB Port 5 119
Camera Arm
5 119
Total Mass 153 3833
Unrequired Components
Final Mass 52814 [g] 12456 [ of stock]
20
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
CONOPS ndash Scenario 2
Continuous signal monitoring and
data transmission detection
Command Destination and Waypoints for autonomous
travel
Downlink and store flight data
in real time
Immediate powerful RFI detected Lose
Communication link with ground station
Abort mission disable GPS and
attempt to return home inertially
Immediate large radius RFI is
enabled
8
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
False GPS sphere of influence
CONOPS ndash Scenario 3
Command Destination and Waypoints for autonomous
travel False Signal Detected
Viable communication link with ground station
Attempt to map sphere of
influence or locate source of RFI
Continuous signal monitoring and
data transmission detection
Downlink and store flight data
in real time
9
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Functional Requirements[1]
REFERENCE Description
1QUADFR1 SIVAQ shall travel autonomously via predetermined waypoints while maintaining pseudo range accuracy of 78
meters (TBR) at 95 confidence level
1QUADFR2
SIVAQ shall monitor GPS information integrity and detect radio frequency interference Signal shall be
considered compromised if AGC level is greater than three from nominal AGC level
1QUADFR3 SIVAQ shall create map RFI zone of influence
1QUADFR4 SIVAQ shall return to ground station once mission is completed or at 30 (TBR) battery life remaining
1QUADFR5 SIVAQ shall be able to fly to a target location within a 3km radius area capture video data for 1 min then return
home
1QUADFR6 Finalized SIVAQ cost shall be less than $750 (TBR) in components
1QUADFR7 SIVAQ shall be operational in open terrain and in conditions of ideal weather (no precipitation and no wind)
1QUADFR8 SIVAQ shall be equipped with an extended range 24 GHz Wi-Fi two-way communications device
1QUADFR9 During 1 minute loiter SIVAQ will provide live video data such that the pilot can identify a red target 1 m2 in a
10000 m2 field
1GRNFR1 A GUI will allow the user to select waypoints and specify the vehicles mission Additionally the user will be able
to alter waypoints during flight
1GRNFR2 The command center must be able to receive and display data sent from the vehicle for processing
10
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Baseline Design Selections[1]
Subsystem Design Selection
RFI detection Automatic Gain Control signal monitoring
Mass and Power Structural modification and high capacity Li-Ion battery
Communications 24 GHz Wi-Fi antenna modification
Mission Data USB flash storage and Wi-Fi 80211n streaming
Control Software AutoPylot written in MATLAB
Navigation method GPS based waypoint navigation
GUI Software NASA WorldWind mapping software and Java Swing
11
CDD Design Solutions
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Feasibility Studies
Aspects of the project analyzed for feasibility
1 How will the vehicle detect and simulate RFI
2 Is 6 km range (3km out and back) possible given mass and power considerations
3 Can the vehicle maintain communication link with the ground station over 3km distance
4 Can vehicle accommodate required data transfer and storage rates
5 Does MATLAB have an acceptable response time for control software
6 Is waypoint style navigation possible with selected software
12
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
Automatic Gain Control
bull Automatic Gain Control (AGC) is an adaptive circuit which dynamically adjusts incoming signal gains to match the level requirement of downstream electronics[4]
bull AGC is low complexity and is intrinsic in all multi-bit GPS receivers
bull AGC is not part of NMEA message but some civilian GPS receivers include it in the digital output
bull GPS RFI can be detected by monitoring the output of the AGC circuitry bull A boosted GPS signal causes the
AGC to drop
13
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
bull A study conducted in Sweden[4] using a GPS RFI device showed that AGC can be used to accurately detect GPS RFI bull AGC output is monitored for a
drop below a predetermined threshold
bull This proves the feasibility of the AGC detection method
14
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AGC Signal Characterization
bull AGC levels are subject to noise from surroundings[3]
bull Refinements can be made to AGC measurements by accounting for thermal noise and other signals present in the frequency band
bull Noise can be characterized for the specific GPS module and flight conditions to properly detect active RFI
15 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - Noise Characterization
bull Ground and Flight models of the GPS modules will be bench tested and data will be logged using a data acquisition system
bull Tests will be run both on and off the UAV platform bull On-platform tests will be run with the vehicle off on and in
controlled flight
bull Results from this test will allow for the characterization of noise in the GPS signal for various conditions
Thermistor
16 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - L1 Injection
bull An L1 GPS signal simulator will be fed through a variable gain amplifier and injected into the GPS RF stream simulating a malicious RFI source
bull A data acquisition system will be used to monitor and log the AGC signal from the GPS module
bull This ground test will be used to characterize AGC response to an amplified signal in the L1 band and determine the appropriate threshold at which AGC will accurately denote GPS RFI
17
Thermistor
RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Waypoint-based RFI Simulation bull To implement RFI in flight (currently illegal) data from RFI ground tests are
used to create a software simulation which mimics the results of actual RFI on the AGC signal in the GPS modulersquos digital output
bull GPS waypoints are used to define the perimeter of the simulated RFI zone which when breached will result in simulated RFI manipulating the digital AGC signal
Nav Software
RFI Software
Thermistor
18 RFI Simulation Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Customer Requirement ARDrone 20 shall fly 3 km from launch point loiter for 60 seconds then return 3 km to takeoff point ARDrone 20 Capabilities Manufacturer Claim 36 km max range (Cruise Speed 5 ms Flight Time 12 minutes) User Claim 225 km max range (Chuck Rossetti claims only Wi-Fi modifications) Drivers for Range Requirement bull Commercially available radio frequency interference devices have extremely
variable areas of influence (up to 6km) but the typical RFI device ldquozone of influencerdquo extends 2 to 500 meters from signal source
bull Extended range improves functionality of ARDrone 20 enables ability to map ldquozonerdquo of GPS corruption
bull Range improvement enables increased flexibility in future missions (Customer Request)
19
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AR Drone Mass Budget
Required Components
Component Mass [g] Percent of Stock Mass []
Stock Outdoor Vehicle
424 10000
GPS ReceiverAntenna
20 472
4000 mAh Battery (Dynamite Speed Pack Silver)
225 4693
Polarized Antenna 11 259
USB 1 024
Magnetic Compass 014 003
Total Mass 68114 16065
Component Mass [g] Percent of Stock Mass []
Outdoor Hull
32 952
1000 mAh Battery
101 2405
Stickers 10 238
USB Port 5 119
Camera Arm
5 119
Total Mass 153 3833
Unrequired Components
Final Mass 52814 [g] 12456 [ of stock]
20
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
False GPS sphere of influence
CONOPS ndash Scenario 3
Command Destination and Waypoints for autonomous
travel False Signal Detected
Viable communication link with ground station
Attempt to map sphere of
influence or locate source of RFI
Continuous signal monitoring and
data transmission detection
Downlink and store flight data
in real time
9
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Functional Requirements[1]
REFERENCE Description
1QUADFR1 SIVAQ shall travel autonomously via predetermined waypoints while maintaining pseudo range accuracy of 78
meters (TBR) at 95 confidence level
1QUADFR2
SIVAQ shall monitor GPS information integrity and detect radio frequency interference Signal shall be
considered compromised if AGC level is greater than three from nominal AGC level
1QUADFR3 SIVAQ shall create map RFI zone of influence
1QUADFR4 SIVAQ shall return to ground station once mission is completed or at 30 (TBR) battery life remaining
1QUADFR5 SIVAQ shall be able to fly to a target location within a 3km radius area capture video data for 1 min then return
home
1QUADFR6 Finalized SIVAQ cost shall be less than $750 (TBR) in components
1QUADFR7 SIVAQ shall be operational in open terrain and in conditions of ideal weather (no precipitation and no wind)
1QUADFR8 SIVAQ shall be equipped with an extended range 24 GHz Wi-Fi two-way communications device
1QUADFR9 During 1 minute loiter SIVAQ will provide live video data such that the pilot can identify a red target 1 m2 in a
10000 m2 field
1GRNFR1 A GUI will allow the user to select waypoints and specify the vehicles mission Additionally the user will be able
to alter waypoints during flight
1GRNFR2 The command center must be able to receive and display data sent from the vehicle for processing
10
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Baseline Design Selections[1]
Subsystem Design Selection
RFI detection Automatic Gain Control signal monitoring
Mass and Power Structural modification and high capacity Li-Ion battery
Communications 24 GHz Wi-Fi antenna modification
Mission Data USB flash storage and Wi-Fi 80211n streaming
Control Software AutoPylot written in MATLAB
Navigation method GPS based waypoint navigation
GUI Software NASA WorldWind mapping software and Java Swing
11
CDD Design Solutions
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Feasibility Studies
Aspects of the project analyzed for feasibility
1 How will the vehicle detect and simulate RFI
2 Is 6 km range (3km out and back) possible given mass and power considerations
3 Can the vehicle maintain communication link with the ground station over 3km distance
4 Can vehicle accommodate required data transfer and storage rates
5 Does MATLAB have an acceptable response time for control software
6 Is waypoint style navigation possible with selected software
12
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
Automatic Gain Control
bull Automatic Gain Control (AGC) is an adaptive circuit which dynamically adjusts incoming signal gains to match the level requirement of downstream electronics[4]
bull AGC is low complexity and is intrinsic in all multi-bit GPS receivers
bull AGC is not part of NMEA message but some civilian GPS receivers include it in the digital output
bull GPS RFI can be detected by monitoring the output of the AGC circuitry bull A boosted GPS signal causes the
AGC to drop
13
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
bull A study conducted in Sweden[4] using a GPS RFI device showed that AGC can be used to accurately detect GPS RFI bull AGC output is monitored for a
drop below a predetermined threshold
bull This proves the feasibility of the AGC detection method
14
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AGC Signal Characterization
bull AGC levels are subject to noise from surroundings[3]
bull Refinements can be made to AGC measurements by accounting for thermal noise and other signals present in the frequency band
bull Noise can be characterized for the specific GPS module and flight conditions to properly detect active RFI
15 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - Noise Characterization
bull Ground and Flight models of the GPS modules will be bench tested and data will be logged using a data acquisition system
bull Tests will be run both on and off the UAV platform bull On-platform tests will be run with the vehicle off on and in
controlled flight
bull Results from this test will allow for the characterization of noise in the GPS signal for various conditions
Thermistor
16 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - L1 Injection
bull An L1 GPS signal simulator will be fed through a variable gain amplifier and injected into the GPS RF stream simulating a malicious RFI source
bull A data acquisition system will be used to monitor and log the AGC signal from the GPS module
bull This ground test will be used to characterize AGC response to an amplified signal in the L1 band and determine the appropriate threshold at which AGC will accurately denote GPS RFI
17
Thermistor
RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Waypoint-based RFI Simulation bull To implement RFI in flight (currently illegal) data from RFI ground tests are
used to create a software simulation which mimics the results of actual RFI on the AGC signal in the GPS modulersquos digital output
bull GPS waypoints are used to define the perimeter of the simulated RFI zone which when breached will result in simulated RFI manipulating the digital AGC signal
Nav Software
RFI Software
Thermistor
18 RFI Simulation Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Customer Requirement ARDrone 20 shall fly 3 km from launch point loiter for 60 seconds then return 3 km to takeoff point ARDrone 20 Capabilities Manufacturer Claim 36 km max range (Cruise Speed 5 ms Flight Time 12 minutes) User Claim 225 km max range (Chuck Rossetti claims only Wi-Fi modifications) Drivers for Range Requirement bull Commercially available radio frequency interference devices have extremely
variable areas of influence (up to 6km) but the typical RFI device ldquozone of influencerdquo extends 2 to 500 meters from signal source
bull Extended range improves functionality of ARDrone 20 enables ability to map ldquozonerdquo of GPS corruption
bull Range improvement enables increased flexibility in future missions (Customer Request)
19
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AR Drone Mass Budget
Required Components
Component Mass [g] Percent of Stock Mass []
Stock Outdoor Vehicle
424 10000
GPS ReceiverAntenna
20 472
4000 mAh Battery (Dynamite Speed Pack Silver)
225 4693
Polarized Antenna 11 259
USB 1 024
Magnetic Compass 014 003
Total Mass 68114 16065
Component Mass [g] Percent of Stock Mass []
Outdoor Hull
32 952
1000 mAh Battery
101 2405
Stickers 10 238
USB Port 5 119
Camera Arm
5 119
Total Mass 153 3833
Unrequired Components
Final Mass 52814 [g] 12456 [ of stock]
20
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Functional Requirements[1]
REFERENCE Description
1QUADFR1 SIVAQ shall travel autonomously via predetermined waypoints while maintaining pseudo range accuracy of 78
meters (TBR) at 95 confidence level
1QUADFR2
SIVAQ shall monitor GPS information integrity and detect radio frequency interference Signal shall be
considered compromised if AGC level is greater than three from nominal AGC level
1QUADFR3 SIVAQ shall create map RFI zone of influence
1QUADFR4 SIVAQ shall return to ground station once mission is completed or at 30 (TBR) battery life remaining
1QUADFR5 SIVAQ shall be able to fly to a target location within a 3km radius area capture video data for 1 min then return
home
1QUADFR6 Finalized SIVAQ cost shall be less than $750 (TBR) in components
1QUADFR7 SIVAQ shall be operational in open terrain and in conditions of ideal weather (no precipitation and no wind)
1QUADFR8 SIVAQ shall be equipped with an extended range 24 GHz Wi-Fi two-way communications device
1QUADFR9 During 1 minute loiter SIVAQ will provide live video data such that the pilot can identify a red target 1 m2 in a
10000 m2 field
1GRNFR1 A GUI will allow the user to select waypoints and specify the vehicles mission Additionally the user will be able
to alter waypoints during flight
1GRNFR2 The command center must be able to receive and display data sent from the vehicle for processing
10
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Baseline Design Selections[1]
Subsystem Design Selection
RFI detection Automatic Gain Control signal monitoring
Mass and Power Structural modification and high capacity Li-Ion battery
Communications 24 GHz Wi-Fi antenna modification
Mission Data USB flash storage and Wi-Fi 80211n streaming
Control Software AutoPylot written in MATLAB
Navigation method GPS based waypoint navigation
GUI Software NASA WorldWind mapping software and Java Swing
11
CDD Design Solutions
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Feasibility Studies
Aspects of the project analyzed for feasibility
1 How will the vehicle detect and simulate RFI
2 Is 6 km range (3km out and back) possible given mass and power considerations
3 Can the vehicle maintain communication link with the ground station over 3km distance
4 Can vehicle accommodate required data transfer and storage rates
5 Does MATLAB have an acceptable response time for control software
6 Is waypoint style navigation possible with selected software
12
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
Automatic Gain Control
bull Automatic Gain Control (AGC) is an adaptive circuit which dynamically adjusts incoming signal gains to match the level requirement of downstream electronics[4]
bull AGC is low complexity and is intrinsic in all multi-bit GPS receivers
bull AGC is not part of NMEA message but some civilian GPS receivers include it in the digital output
bull GPS RFI can be detected by monitoring the output of the AGC circuitry bull A boosted GPS signal causes the
AGC to drop
13
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
bull A study conducted in Sweden[4] using a GPS RFI device showed that AGC can be used to accurately detect GPS RFI bull AGC output is monitored for a
drop below a predetermined threshold
bull This proves the feasibility of the AGC detection method
14
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AGC Signal Characterization
bull AGC levels are subject to noise from surroundings[3]
bull Refinements can be made to AGC measurements by accounting for thermal noise and other signals present in the frequency band
bull Noise can be characterized for the specific GPS module and flight conditions to properly detect active RFI
15 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - Noise Characterization
bull Ground and Flight models of the GPS modules will be bench tested and data will be logged using a data acquisition system
bull Tests will be run both on and off the UAV platform bull On-platform tests will be run with the vehicle off on and in
controlled flight
bull Results from this test will allow for the characterization of noise in the GPS signal for various conditions
Thermistor
16 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - L1 Injection
bull An L1 GPS signal simulator will be fed through a variable gain amplifier and injected into the GPS RF stream simulating a malicious RFI source
bull A data acquisition system will be used to monitor and log the AGC signal from the GPS module
bull This ground test will be used to characterize AGC response to an amplified signal in the L1 band and determine the appropriate threshold at which AGC will accurately denote GPS RFI
17
Thermistor
RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Waypoint-based RFI Simulation bull To implement RFI in flight (currently illegal) data from RFI ground tests are
used to create a software simulation which mimics the results of actual RFI on the AGC signal in the GPS modulersquos digital output
bull GPS waypoints are used to define the perimeter of the simulated RFI zone which when breached will result in simulated RFI manipulating the digital AGC signal
Nav Software
RFI Software
Thermistor
18 RFI Simulation Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Customer Requirement ARDrone 20 shall fly 3 km from launch point loiter for 60 seconds then return 3 km to takeoff point ARDrone 20 Capabilities Manufacturer Claim 36 km max range (Cruise Speed 5 ms Flight Time 12 minutes) User Claim 225 km max range (Chuck Rossetti claims only Wi-Fi modifications) Drivers for Range Requirement bull Commercially available radio frequency interference devices have extremely
variable areas of influence (up to 6km) but the typical RFI device ldquozone of influencerdquo extends 2 to 500 meters from signal source
bull Extended range improves functionality of ARDrone 20 enables ability to map ldquozonerdquo of GPS corruption
bull Range improvement enables increased flexibility in future missions (Customer Request)
19
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AR Drone Mass Budget
Required Components
Component Mass [g] Percent of Stock Mass []
Stock Outdoor Vehicle
424 10000
GPS ReceiverAntenna
20 472
4000 mAh Battery (Dynamite Speed Pack Silver)
225 4693
Polarized Antenna 11 259
USB 1 024
Magnetic Compass 014 003
Total Mass 68114 16065
Component Mass [g] Percent of Stock Mass []
Outdoor Hull
32 952
1000 mAh Battery
101 2405
Stickers 10 238
USB Port 5 119
Camera Arm
5 119
Total Mass 153 3833
Unrequired Components
Final Mass 52814 [g] 12456 [ of stock]
20
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Baseline Design Selections[1]
Subsystem Design Selection
RFI detection Automatic Gain Control signal monitoring
Mass and Power Structural modification and high capacity Li-Ion battery
Communications 24 GHz Wi-Fi antenna modification
Mission Data USB flash storage and Wi-Fi 80211n streaming
Control Software AutoPylot written in MATLAB
Navigation method GPS based waypoint navigation
GUI Software NASA WorldWind mapping software and Java Swing
11
CDD Design Solutions
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Feasibility Studies
Aspects of the project analyzed for feasibility
1 How will the vehicle detect and simulate RFI
2 Is 6 km range (3km out and back) possible given mass and power considerations
3 Can the vehicle maintain communication link with the ground station over 3km distance
4 Can vehicle accommodate required data transfer and storage rates
5 Does MATLAB have an acceptable response time for control software
6 Is waypoint style navigation possible with selected software
12
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
Automatic Gain Control
bull Automatic Gain Control (AGC) is an adaptive circuit which dynamically adjusts incoming signal gains to match the level requirement of downstream electronics[4]
bull AGC is low complexity and is intrinsic in all multi-bit GPS receivers
bull AGC is not part of NMEA message but some civilian GPS receivers include it in the digital output
bull GPS RFI can be detected by monitoring the output of the AGC circuitry bull A boosted GPS signal causes the
AGC to drop
13
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
bull A study conducted in Sweden[4] using a GPS RFI device showed that AGC can be used to accurately detect GPS RFI bull AGC output is monitored for a
drop below a predetermined threshold
bull This proves the feasibility of the AGC detection method
14
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AGC Signal Characterization
bull AGC levels are subject to noise from surroundings[3]
bull Refinements can be made to AGC measurements by accounting for thermal noise and other signals present in the frequency band
bull Noise can be characterized for the specific GPS module and flight conditions to properly detect active RFI
15 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - Noise Characterization
bull Ground and Flight models of the GPS modules will be bench tested and data will be logged using a data acquisition system
bull Tests will be run both on and off the UAV platform bull On-platform tests will be run with the vehicle off on and in
controlled flight
bull Results from this test will allow for the characterization of noise in the GPS signal for various conditions
Thermistor
16 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - L1 Injection
bull An L1 GPS signal simulator will be fed through a variable gain amplifier and injected into the GPS RF stream simulating a malicious RFI source
bull A data acquisition system will be used to monitor and log the AGC signal from the GPS module
bull This ground test will be used to characterize AGC response to an amplified signal in the L1 band and determine the appropriate threshold at which AGC will accurately denote GPS RFI
17
Thermistor
RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Waypoint-based RFI Simulation bull To implement RFI in flight (currently illegal) data from RFI ground tests are
used to create a software simulation which mimics the results of actual RFI on the AGC signal in the GPS modulersquos digital output
bull GPS waypoints are used to define the perimeter of the simulated RFI zone which when breached will result in simulated RFI manipulating the digital AGC signal
Nav Software
RFI Software
Thermistor
18 RFI Simulation Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Customer Requirement ARDrone 20 shall fly 3 km from launch point loiter for 60 seconds then return 3 km to takeoff point ARDrone 20 Capabilities Manufacturer Claim 36 km max range (Cruise Speed 5 ms Flight Time 12 minutes) User Claim 225 km max range (Chuck Rossetti claims only Wi-Fi modifications) Drivers for Range Requirement bull Commercially available radio frequency interference devices have extremely
variable areas of influence (up to 6km) but the typical RFI device ldquozone of influencerdquo extends 2 to 500 meters from signal source
bull Extended range improves functionality of ARDrone 20 enables ability to map ldquozonerdquo of GPS corruption
bull Range improvement enables increased flexibility in future missions (Customer Request)
19
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AR Drone Mass Budget
Required Components
Component Mass [g] Percent of Stock Mass []
Stock Outdoor Vehicle
424 10000
GPS ReceiverAntenna
20 472
4000 mAh Battery (Dynamite Speed Pack Silver)
225 4693
Polarized Antenna 11 259
USB 1 024
Magnetic Compass 014 003
Total Mass 68114 16065
Component Mass [g] Percent of Stock Mass []
Outdoor Hull
32 952
1000 mAh Battery
101 2405
Stickers 10 238
USB Port 5 119
Camera Arm
5 119
Total Mass 153 3833
Unrequired Components
Final Mass 52814 [g] 12456 [ of stock]
20
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Feasibility Studies
Aspects of the project analyzed for feasibility
1 How will the vehicle detect and simulate RFI
2 Is 6 km range (3km out and back) possible given mass and power considerations
3 Can the vehicle maintain communication link with the ground station over 3km distance
4 Can vehicle accommodate required data transfer and storage rates
5 Does MATLAB have an acceptable response time for control software
6 Is waypoint style navigation possible with selected software
12
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
Automatic Gain Control
bull Automatic Gain Control (AGC) is an adaptive circuit which dynamically adjusts incoming signal gains to match the level requirement of downstream electronics[4]
bull AGC is low complexity and is intrinsic in all multi-bit GPS receivers
bull AGC is not part of NMEA message but some civilian GPS receivers include it in the digital output
bull GPS RFI can be detected by monitoring the output of the AGC circuitry bull A boosted GPS signal causes the
AGC to drop
13
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
bull A study conducted in Sweden[4] using a GPS RFI device showed that AGC can be used to accurately detect GPS RFI bull AGC output is monitored for a
drop below a predetermined threshold
bull This proves the feasibility of the AGC detection method
14
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AGC Signal Characterization
bull AGC levels are subject to noise from surroundings[3]
bull Refinements can be made to AGC measurements by accounting for thermal noise and other signals present in the frequency band
bull Noise can be characterized for the specific GPS module and flight conditions to properly detect active RFI
15 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - Noise Characterization
bull Ground and Flight models of the GPS modules will be bench tested and data will be logged using a data acquisition system
bull Tests will be run both on and off the UAV platform bull On-platform tests will be run with the vehicle off on and in
controlled flight
bull Results from this test will allow for the characterization of noise in the GPS signal for various conditions
Thermistor
16 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - L1 Injection
bull An L1 GPS signal simulator will be fed through a variable gain amplifier and injected into the GPS RF stream simulating a malicious RFI source
bull A data acquisition system will be used to monitor and log the AGC signal from the GPS module
bull This ground test will be used to characterize AGC response to an amplified signal in the L1 band and determine the appropriate threshold at which AGC will accurately denote GPS RFI
17
Thermistor
RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Waypoint-based RFI Simulation bull To implement RFI in flight (currently illegal) data from RFI ground tests are
used to create a software simulation which mimics the results of actual RFI on the AGC signal in the GPS modulersquos digital output
bull GPS waypoints are used to define the perimeter of the simulated RFI zone which when breached will result in simulated RFI manipulating the digital AGC signal
Nav Software
RFI Software
Thermistor
18 RFI Simulation Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Customer Requirement ARDrone 20 shall fly 3 km from launch point loiter for 60 seconds then return 3 km to takeoff point ARDrone 20 Capabilities Manufacturer Claim 36 km max range (Cruise Speed 5 ms Flight Time 12 minutes) User Claim 225 km max range (Chuck Rossetti claims only Wi-Fi modifications) Drivers for Range Requirement bull Commercially available radio frequency interference devices have extremely
variable areas of influence (up to 6km) but the typical RFI device ldquozone of influencerdquo extends 2 to 500 meters from signal source
bull Extended range improves functionality of ARDrone 20 enables ability to map ldquozonerdquo of GPS corruption
bull Range improvement enables increased flexibility in future missions (Customer Request)
19
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AR Drone Mass Budget
Required Components
Component Mass [g] Percent of Stock Mass []
Stock Outdoor Vehicle
424 10000
GPS ReceiverAntenna
20 472
4000 mAh Battery (Dynamite Speed Pack Silver)
225 4693
Polarized Antenna 11 259
USB 1 024
Magnetic Compass 014 003
Total Mass 68114 16065
Component Mass [g] Percent of Stock Mass []
Outdoor Hull
32 952
1000 mAh Battery
101 2405
Stickers 10 238
USB Port 5 119
Camera Arm
5 119
Total Mass 153 3833
Unrequired Components
Final Mass 52814 [g] 12456 [ of stock]
20
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
Automatic Gain Control
bull Automatic Gain Control (AGC) is an adaptive circuit which dynamically adjusts incoming signal gains to match the level requirement of downstream electronics[4]
bull AGC is low complexity and is intrinsic in all multi-bit GPS receivers
bull AGC is not part of NMEA message but some civilian GPS receivers include it in the digital output
bull GPS RFI can be detected by monitoring the output of the AGC circuitry bull A boosted GPS signal causes the
AGC to drop
13
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
bull A study conducted in Sweden[4] using a GPS RFI device showed that AGC can be used to accurately detect GPS RFI bull AGC output is monitored for a
drop below a predetermined threshold
bull This proves the feasibility of the AGC detection method
14
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AGC Signal Characterization
bull AGC levels are subject to noise from surroundings[3]
bull Refinements can be made to AGC measurements by accounting for thermal noise and other signals present in the frequency band
bull Noise can be characterized for the specific GPS module and flight conditions to properly detect active RFI
15 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - Noise Characterization
bull Ground and Flight models of the GPS modules will be bench tested and data will be logged using a data acquisition system
bull Tests will be run both on and off the UAV platform bull On-platform tests will be run with the vehicle off on and in
controlled flight
bull Results from this test will allow for the characterization of noise in the GPS signal for various conditions
Thermistor
16 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - L1 Injection
bull An L1 GPS signal simulator will be fed through a variable gain amplifier and injected into the GPS RF stream simulating a malicious RFI source
bull A data acquisition system will be used to monitor and log the AGC signal from the GPS module
bull This ground test will be used to characterize AGC response to an amplified signal in the L1 band and determine the appropriate threshold at which AGC will accurately denote GPS RFI
17
Thermistor
RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Waypoint-based RFI Simulation bull To implement RFI in flight (currently illegal) data from RFI ground tests are
used to create a software simulation which mimics the results of actual RFI on the AGC signal in the GPS modulersquos digital output
bull GPS waypoints are used to define the perimeter of the simulated RFI zone which when breached will result in simulated RFI manipulating the digital AGC signal
Nav Software
RFI Software
Thermistor
18 RFI Simulation Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Customer Requirement ARDrone 20 shall fly 3 km from launch point loiter for 60 seconds then return 3 km to takeoff point ARDrone 20 Capabilities Manufacturer Claim 36 km max range (Cruise Speed 5 ms Flight Time 12 minutes) User Claim 225 km max range (Chuck Rossetti claims only Wi-Fi modifications) Drivers for Range Requirement bull Commercially available radio frequency interference devices have extremely
variable areas of influence (up to 6km) but the typical RFI device ldquozone of influencerdquo extends 2 to 500 meters from signal source
bull Extended range improves functionality of ARDrone 20 enables ability to map ldquozonerdquo of GPS corruption
bull Range improvement enables increased flexibility in future missions (Customer Request)
19
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AR Drone Mass Budget
Required Components
Component Mass [g] Percent of Stock Mass []
Stock Outdoor Vehicle
424 10000
GPS ReceiverAntenna
20 472
4000 mAh Battery (Dynamite Speed Pack Silver)
225 4693
Polarized Antenna 11 259
USB 1 024
Magnetic Compass 014 003
Total Mass 68114 16065
Component Mass [g] Percent of Stock Mass []
Outdoor Hull
32 952
1000 mAh Battery
101 2405
Stickers 10 238
USB Port 5 119
Camera Arm
5 119
Total Mass 153 3833
Unrequired Components
Final Mass 52814 [g] 12456 [ of stock]
20
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Detection Feasibility
bull A study conducted in Sweden[4] using a GPS RFI device showed that AGC can be used to accurately detect GPS RFI bull AGC output is monitored for a
drop below a predetermined threshold
bull This proves the feasibility of the AGC detection method
14
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AGC Signal Characterization
bull AGC levels are subject to noise from surroundings[3]
bull Refinements can be made to AGC measurements by accounting for thermal noise and other signals present in the frequency band
bull Noise can be characterized for the specific GPS module and flight conditions to properly detect active RFI
15 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - Noise Characterization
bull Ground and Flight models of the GPS modules will be bench tested and data will be logged using a data acquisition system
bull Tests will be run both on and off the UAV platform bull On-platform tests will be run with the vehicle off on and in
controlled flight
bull Results from this test will allow for the characterization of noise in the GPS signal for various conditions
Thermistor
16 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - L1 Injection
bull An L1 GPS signal simulator will be fed through a variable gain amplifier and injected into the GPS RF stream simulating a malicious RFI source
bull A data acquisition system will be used to monitor and log the AGC signal from the GPS module
bull This ground test will be used to characterize AGC response to an amplified signal in the L1 band and determine the appropriate threshold at which AGC will accurately denote GPS RFI
17
Thermistor
RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Waypoint-based RFI Simulation bull To implement RFI in flight (currently illegal) data from RFI ground tests are
used to create a software simulation which mimics the results of actual RFI on the AGC signal in the GPS modulersquos digital output
bull GPS waypoints are used to define the perimeter of the simulated RFI zone which when breached will result in simulated RFI manipulating the digital AGC signal
Nav Software
RFI Software
Thermistor
18 RFI Simulation Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Customer Requirement ARDrone 20 shall fly 3 km from launch point loiter for 60 seconds then return 3 km to takeoff point ARDrone 20 Capabilities Manufacturer Claim 36 km max range (Cruise Speed 5 ms Flight Time 12 minutes) User Claim 225 km max range (Chuck Rossetti claims only Wi-Fi modifications) Drivers for Range Requirement bull Commercially available radio frequency interference devices have extremely
variable areas of influence (up to 6km) but the typical RFI device ldquozone of influencerdquo extends 2 to 500 meters from signal source
bull Extended range improves functionality of ARDrone 20 enables ability to map ldquozonerdquo of GPS corruption
bull Range improvement enables increased flexibility in future missions (Customer Request)
19
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AR Drone Mass Budget
Required Components
Component Mass [g] Percent of Stock Mass []
Stock Outdoor Vehicle
424 10000
GPS ReceiverAntenna
20 472
4000 mAh Battery (Dynamite Speed Pack Silver)
225 4693
Polarized Antenna 11 259
USB 1 024
Magnetic Compass 014 003
Total Mass 68114 16065
Component Mass [g] Percent of Stock Mass []
Outdoor Hull
32 952
1000 mAh Battery
101 2405
Stickers 10 238
USB Port 5 119
Camera Arm
5 119
Total Mass 153 3833
Unrequired Components
Final Mass 52814 [g] 12456 [ of stock]
20
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AGC Signal Characterization
bull AGC levels are subject to noise from surroundings[3]
bull Refinements can be made to AGC measurements by accounting for thermal noise and other signals present in the frequency band
bull Noise can be characterized for the specific GPS module and flight conditions to properly detect active RFI
15 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - Noise Characterization
bull Ground and Flight models of the GPS modules will be bench tested and data will be logged using a data acquisition system
bull Tests will be run both on and off the UAV platform bull On-platform tests will be run with the vehicle off on and in
controlled flight
bull Results from this test will allow for the characterization of noise in the GPS signal for various conditions
Thermistor
16 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - L1 Injection
bull An L1 GPS signal simulator will be fed through a variable gain amplifier and injected into the GPS RF stream simulating a malicious RFI source
bull A data acquisition system will be used to monitor and log the AGC signal from the GPS module
bull This ground test will be used to characterize AGC response to an amplified signal in the L1 band and determine the appropriate threshold at which AGC will accurately denote GPS RFI
17
Thermistor
RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Waypoint-based RFI Simulation bull To implement RFI in flight (currently illegal) data from RFI ground tests are
used to create a software simulation which mimics the results of actual RFI on the AGC signal in the GPS modulersquos digital output
bull GPS waypoints are used to define the perimeter of the simulated RFI zone which when breached will result in simulated RFI manipulating the digital AGC signal
Nav Software
RFI Software
Thermistor
18 RFI Simulation Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Customer Requirement ARDrone 20 shall fly 3 km from launch point loiter for 60 seconds then return 3 km to takeoff point ARDrone 20 Capabilities Manufacturer Claim 36 km max range (Cruise Speed 5 ms Flight Time 12 minutes) User Claim 225 km max range (Chuck Rossetti claims only Wi-Fi modifications) Drivers for Range Requirement bull Commercially available radio frequency interference devices have extremely
variable areas of influence (up to 6km) but the typical RFI device ldquozone of influencerdquo extends 2 to 500 meters from signal source
bull Extended range improves functionality of ARDrone 20 enables ability to map ldquozonerdquo of GPS corruption
bull Range improvement enables increased flexibility in future missions (Customer Request)
19
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AR Drone Mass Budget
Required Components
Component Mass [g] Percent of Stock Mass []
Stock Outdoor Vehicle
424 10000
GPS ReceiverAntenna
20 472
4000 mAh Battery (Dynamite Speed Pack Silver)
225 4693
Polarized Antenna 11 259
USB 1 024
Magnetic Compass 014 003
Total Mass 68114 16065
Component Mass [g] Percent of Stock Mass []
Outdoor Hull
32 952
1000 mAh Battery
101 2405
Stickers 10 238
USB Port 5 119
Camera Arm
5 119
Total Mass 153 3833
Unrequired Components
Final Mass 52814 [g] 12456 [ of stock]
20
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - Noise Characterization
bull Ground and Flight models of the GPS modules will be bench tested and data will be logged using a data acquisition system
bull Tests will be run both on and off the UAV platform bull On-platform tests will be run with the vehicle off on and in
controlled flight
bull Results from this test will allow for the characterization of noise in the GPS signal for various conditions
Thermistor
16 RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - L1 Injection
bull An L1 GPS signal simulator will be fed through a variable gain amplifier and injected into the GPS RF stream simulating a malicious RFI source
bull A data acquisition system will be used to monitor and log the AGC signal from the GPS module
bull This ground test will be used to characterize AGC response to an amplified signal in the L1 band and determine the appropriate threshold at which AGC will accurately denote GPS RFI
17
Thermistor
RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Waypoint-based RFI Simulation bull To implement RFI in flight (currently illegal) data from RFI ground tests are
used to create a software simulation which mimics the results of actual RFI on the AGC signal in the GPS modulersquos digital output
bull GPS waypoints are used to define the perimeter of the simulated RFI zone which when breached will result in simulated RFI manipulating the digital AGC signal
Nav Software
RFI Software
Thermistor
18 RFI Simulation Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Customer Requirement ARDrone 20 shall fly 3 km from launch point loiter for 60 seconds then return 3 km to takeoff point ARDrone 20 Capabilities Manufacturer Claim 36 km max range (Cruise Speed 5 ms Flight Time 12 minutes) User Claim 225 km max range (Chuck Rossetti claims only Wi-Fi modifications) Drivers for Range Requirement bull Commercially available radio frequency interference devices have extremely
variable areas of influence (up to 6km) but the typical RFI device ldquozone of influencerdquo extends 2 to 500 meters from signal source
bull Extended range improves functionality of ARDrone 20 enables ability to map ldquozonerdquo of GPS corruption
bull Range improvement enables increased flexibility in future missions (Customer Request)
19
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AR Drone Mass Budget
Required Components
Component Mass [g] Percent of Stock Mass []
Stock Outdoor Vehicle
424 10000
GPS ReceiverAntenna
20 472
4000 mAh Battery (Dynamite Speed Pack Silver)
225 4693
Polarized Antenna 11 259
USB 1 024
Magnetic Compass 014 003
Total Mass 68114 16065
Component Mass [g] Percent of Stock Mass []
Outdoor Hull
32 952
1000 mAh Battery
101 2405
Stickers 10 238
USB Port 5 119
Camera Arm
5 119
Total Mass 153 3833
Unrequired Components
Final Mass 52814 [g] 12456 [ of stock]
20
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI Ground Testing - L1 Injection
bull An L1 GPS signal simulator will be fed through a variable gain amplifier and injected into the GPS RF stream simulating a malicious RFI source
bull A data acquisition system will be used to monitor and log the AGC signal from the GPS module
bull This ground test will be used to characterize AGC response to an amplified signal in the L1 band and determine the appropriate threshold at which AGC will accurately denote GPS RFI
17
Thermistor
RFI Detection Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Waypoint-based RFI Simulation bull To implement RFI in flight (currently illegal) data from RFI ground tests are
used to create a software simulation which mimics the results of actual RFI on the AGC signal in the GPS modulersquos digital output
bull GPS waypoints are used to define the perimeter of the simulated RFI zone which when breached will result in simulated RFI manipulating the digital AGC signal
Nav Software
RFI Software
Thermistor
18 RFI Simulation Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Customer Requirement ARDrone 20 shall fly 3 km from launch point loiter for 60 seconds then return 3 km to takeoff point ARDrone 20 Capabilities Manufacturer Claim 36 km max range (Cruise Speed 5 ms Flight Time 12 minutes) User Claim 225 km max range (Chuck Rossetti claims only Wi-Fi modifications) Drivers for Range Requirement bull Commercially available radio frequency interference devices have extremely
variable areas of influence (up to 6km) but the typical RFI device ldquozone of influencerdquo extends 2 to 500 meters from signal source
bull Extended range improves functionality of ARDrone 20 enables ability to map ldquozonerdquo of GPS corruption
bull Range improvement enables increased flexibility in future missions (Customer Request)
19
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AR Drone Mass Budget
Required Components
Component Mass [g] Percent of Stock Mass []
Stock Outdoor Vehicle
424 10000
GPS ReceiverAntenna
20 472
4000 mAh Battery (Dynamite Speed Pack Silver)
225 4693
Polarized Antenna 11 259
USB 1 024
Magnetic Compass 014 003
Total Mass 68114 16065
Component Mass [g] Percent of Stock Mass []
Outdoor Hull
32 952
1000 mAh Battery
101 2405
Stickers 10 238
USB Port 5 119
Camera Arm
5 119
Total Mass 153 3833
Unrequired Components
Final Mass 52814 [g] 12456 [ of stock]
20
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Waypoint-based RFI Simulation bull To implement RFI in flight (currently illegal) data from RFI ground tests are
used to create a software simulation which mimics the results of actual RFI on the AGC signal in the GPS modulersquos digital output
bull GPS waypoints are used to define the perimeter of the simulated RFI zone which when breached will result in simulated RFI manipulating the digital AGC signal
Nav Software
RFI Software
Thermistor
18 RFI Simulation Feasibility
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Customer Requirement ARDrone 20 shall fly 3 km from launch point loiter for 60 seconds then return 3 km to takeoff point ARDrone 20 Capabilities Manufacturer Claim 36 km max range (Cruise Speed 5 ms Flight Time 12 minutes) User Claim 225 km max range (Chuck Rossetti claims only Wi-Fi modifications) Drivers for Range Requirement bull Commercially available radio frequency interference devices have extremely
variable areas of influence (up to 6km) but the typical RFI device ldquozone of influencerdquo extends 2 to 500 meters from signal source
bull Extended range improves functionality of ARDrone 20 enables ability to map ldquozonerdquo of GPS corruption
bull Range improvement enables increased flexibility in future missions (Customer Request)
19
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AR Drone Mass Budget
Required Components
Component Mass [g] Percent of Stock Mass []
Stock Outdoor Vehicle
424 10000
GPS ReceiverAntenna
20 472
4000 mAh Battery (Dynamite Speed Pack Silver)
225 4693
Polarized Antenna 11 259
USB 1 024
Magnetic Compass 014 003
Total Mass 68114 16065
Component Mass [g] Percent of Stock Mass []
Outdoor Hull
32 952
1000 mAh Battery
101 2405
Stickers 10 238
USB Port 5 119
Camera Arm
5 119
Total Mass 153 3833
Unrequired Components
Final Mass 52814 [g] 12456 [ of stock]
20
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Customer Requirement ARDrone 20 shall fly 3 km from launch point loiter for 60 seconds then return 3 km to takeoff point ARDrone 20 Capabilities Manufacturer Claim 36 km max range (Cruise Speed 5 ms Flight Time 12 minutes) User Claim 225 km max range (Chuck Rossetti claims only Wi-Fi modifications) Drivers for Range Requirement bull Commercially available radio frequency interference devices have extremely
variable areas of influence (up to 6km) but the typical RFI device ldquozone of influencerdquo extends 2 to 500 meters from signal source
bull Extended range improves functionality of ARDrone 20 enables ability to map ldquozonerdquo of GPS corruption
bull Range improvement enables increased flexibility in future missions (Customer Request)
19
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AR Drone Mass Budget
Required Components
Component Mass [g] Percent of Stock Mass []
Stock Outdoor Vehicle
424 10000
GPS ReceiverAntenna
20 472
4000 mAh Battery (Dynamite Speed Pack Silver)
225 4693
Polarized Antenna 11 259
USB 1 024
Magnetic Compass 014 003
Total Mass 68114 16065
Component Mass [g] Percent of Stock Mass []
Outdoor Hull
32 952
1000 mAh Battery
101 2405
Stickers 10 238
USB Port 5 119
Camera Arm
5 119
Total Mass 153 3833
Unrequired Components
Final Mass 52814 [g] 12456 [ of stock]
20
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
AR Drone Mass Budget
Required Components
Component Mass [g] Percent of Stock Mass []
Stock Outdoor Vehicle
424 10000
GPS ReceiverAntenna
20 472
4000 mAh Battery (Dynamite Speed Pack Silver)
225 4693
Polarized Antenna 11 259
USB 1 024
Magnetic Compass 014 003
Total Mass 68114 16065
Component Mass [g] Percent of Stock Mass []
Outdoor Hull
32 952
1000 mAh Battery
101 2405
Stickers 10 238
USB Port 5 119
Camera Arm
5 119
Total Mass 153 3833
Unrequired Components
Final Mass 52814 [g] 12456 [ of stock]
20
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
STEP 1 Find current during hover STEP 2 Find flight angle at designated speed
Weight
Ampshover
Thrust
A Battery Pack
Angle
Weight Thrust
Velocity
Estimating Current Draw
21
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis
Power Draw Estimation for 6 km distance and 3600 m2 scan
Component Current [Amps]
Battery Capacity [mAh]
Percent of 4000 mAh Battery []
GPS ReceiverAntenna 0075 3133 078
USB 0050 209 050
Flight 692 32831 8208
Scan 692 68 017
Battery Margin NA 8000 20
Total 7045 41421 10355
Stock hardware processing and telemetry of AR Drone 20 is included in flight and scan
The necessary battery capacity to complete the mission is larger than the heaviest allowed battery
22
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Range Feasibility Analysis B
atte
ry M
ass
[g]
Capacity [mAh]
0
0 5000
250
Battery Mass to Capacity Ratio Study
23
Design Area
Unfeasible Area
Needed to fulfill 6km requirement
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication
Requirements bull Vehicle must continuously transmit live video data to the ground station
bull A pilot at the ground station must be able to send vehicle ldquokillrdquo command (FAA Requirement)[5]
bull User must be able to dynamically change waypoints mid-flight
Vehicle is equipped to communicate via Wi-Fi bull Average Wi-Fi range over 80211 protocol is when outdoors
bull This will not reach the suggested travel distance of 3 km
bull The communication capability must be upgraded in some way in order to maintain a high quality data link at the suggested range
24
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Communication Modification
Antenna Modification bull Baseline communication range calculation
bull Normal Wi-Fi range 100m
bull Signal strength drops with range squared so for each doubling of range we need 6dB more signal gain the range must be doubled 5 times (30dB gain) in order to achieve 3km distance assuming no transmission loss
bull Further testing will be necessary to obtain transmission data from the vehicles antenna
bull Must also consider FCC regulations and may not exceed 1W (30dBm) TRP 4W (36dBm) EIRP
bull Highest gain commercially available omnidirectional antenna found was only 15 dB
For point-to-point link antenna gain can be increased to obtain EIRP gt 36dBm but for every 3dBi increase in antenna gain transmit power must be decreased 1dBm
bull 3km range cannot be obtained legally using omnidirectional antenna
bull Online user ldquoGarrockrdquo has created and provides detailed descriptions of what he labels a ldquoWheel Antenna Modrdquo [6] which modifies the vehicles built in antenna to increase the transmission capability to a range of 200m
bull Several users have successfully used the Itelite SRA24019 A 19 dBi directional gain antenna on the ground station to increase the range of the vehicle to a distance of 1 km [7]
25
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transfer and Storage
Requirement bull Data Storage
bull GPS integrity information location velocity heading IMU and other sensor data
bull Data Streaming bull Constant real time video
bull Kill command
bull GPS integrity information location velocity heading IMU and other sensor data
bull GPS Integrity Info
26
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Transmission Feasibility
Data Transmission Rates of On-Board Electronics
The vehicle will be able to transmit all necessary data to the ground station If Wi-Fi power drops below threshold streamed info will be buffered but still
come through
27
Invensense IMU ndash 3000
Front Facing Camera
Down Facing Camera
GPS Battery Levels
Needed Data Rate
Atheros AR 61036
Capability[3]
Data Rates
2 MBs∆ 05 MBs 0167 MBsΩ 0075 MBs 1 MBs∆ 374 MBs 1 MBs ndash 9 MBs
Values used in table represent upper limit of data rates found in research ∆ Functions of sampling rate (IMU sampling at 32 ms)
Ω Assumed to be 13 of front facing camera because resolution is 120p at 60 fps vs front facing camerarsquos 720p at 30 fps Further testing is required to verify resolution Average used as Wi-Fi data sheet reads Further testing required to verify
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Data Storage Feasibility
Data rate excludes video ndash not being stored Assuming a 20 minute flight
Data Storage for On-Board Electronics
Required Data Rate
Required Storage Capacity
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Write Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive
Read Speed
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive Capacity
3075 MBs 4 GB 14 MBs 27 MBs 16 GB
Verbatim Tuff-lsquoNrsquo-Tiny USB Drive only weighs 1 g[8] by far the lighted storage device found to meet project storage needs
USB Drive can store approximately 80 min of flight data 4 x faster than the necessary data rate
28
Additionally the onboard ARM Cortex A8 is capable of writing at 20 MBs over USB[12]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Onboard Software Requirement
bull On-board software must allow for autonomous waypoint navigation
bull Must integrate the AR Dronersquos control algorithms
bull Team familiarity more important than performance
AutoPylot Control Software bull FreeOpen Source
bull C Python and MATLAB integration
bull Runs using AR Dronersquos control algorithms
Language Performance (MIPS)
Threading Estimated Response Time [msMega-Instruction]
C 2000 Yes 5
Python 400[9] No 25
MATLAB 300[2] Yes 333
bull MATLAB compiled to binary using MEx to run on vehicle bull AutoPylot with MATLAB chosen for familiarity with language has acceptable
response delay
29
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation 30
AutoPylot[13]
bull Developed for 64-bit Linux
bull Compiles ARDrone 20 SDK using latest vehicle firmware bull Preserves Parrot calibrated control algorithms
bull Capable of working with with MATLAB using Mex to compile binaries
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Autonomous Waypoint Navigation
U e D G
W
Y +
-
+
+
bull Parrot currently manufactures and sells its own GPS module thus the latest vehicle firmware is already capable of interpreting GPS signal data
bull AutoPylot uses a ldquocommandsrdquo matrix that it sends to the vehicles onboard processing unit
bull The commands matrix contains values for roll pitch yaw zap and gaz that move the vehicle
bull A transformation that creates these commands from GPS position will need to be developed
bull Waypoint navigation with the AR Drone 20 has been successfully completed by several users and institutions including the Delft University of Technology [10]
bull Waypoint Navigation is Feasible
Variable Description
U Destination (Lat Lon Alt)
e Error between current and desired position
D AutoPylot control commands (zap phi theta gaz psi)
G Vehicle built in dynamics and flight control
W External disturbances altering position (wind)
Y Current location (Lat Lon Alt)
31
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Software
The GUI must bull Allow user to select waypoints by clicking on a map
These waypoints are then communicated to the vehicle real-time and can be changed mid-flight
bull Display real time video data streamed from the vehicle
bull Enable quick use of a ldquokillrdquo command
bull Allow user to monitor telemetry data (battery life location velocity connectivity GPS integrity)
bull NASArsquos WorldWind was selected for API support and team familiarity with Java bull Alternative is currently Marble (uses Python)
32
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
GUI Mockup 33
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Further Feasibility Studies
bull Determine if navigation with vehiclersquos IMU and other sensors bring vehicle ldquohomerdquo within acceptable error without the aid of GPS
bull Determine most efficient RFI mapping method
34
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Navigation Without GPS
Customer Requirement ARDrone 20 shall be able to return home when GPS signal integrity is compromised using a secondary navigation system Solution The ARDronersquos velocity measurements will be integrated in both horizontal axes to calculate the ARDronersquos position This will then be used for navigation back to the home base
Known GPS
Lat 405843
N
Lon 1049212
W
X 1243 M
Y 345 M
Last Known GPS
Lat 400176
N
Lon 1052797
W
X 0 m
Y 0 m
Vy
Vx
35
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Inertial Navigation Testing 36
[15]
bull Assuming 3 km path traveled at 4 ms and 05 ms error distance error would accumulate to 375 m
Test Method Flight test logging GPS and IMU data and compare
Time [s]
Spee
d [
ms
]
Method AR Drone calculates velocity by integrating accelerometer measurements corrected by down-facing camera Precision of accelerometers is added to the steady accuracy of the camera to provide a velocity solution that does not compound error and a position solution that compounds linearly rather than exponentially
Velocity Estimation
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
RFI zone of influence mapping
bull Mapping technique is going to depend highly upon AGC lab measurements as well as onboard processor availability
bull Lab testing will need to determine nominal AGC value as well as necessary change that corresponds to RFI
bull Once this is known appropriate mapping algorithm will be developed
bull In addition to mapping technique minimizing total distance traveled without sacrificing map accuracy is desired
37
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
38 RFI Mapping preliminary CONOPS
AGC threshold crossed Store
last known good location
AGC level returned above
threshold Store location
D2 lt D1Mapping completed return
home
d2
AGC value again trusted store
latitude distance between good
locations d1
38
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
39 Feasibility Summary
Subsystem Feasible Reason
RFI Yes Previous testing demonstrated feasibility
Mass and Power No MATLAB model showed unfeasibility with commercially available batteries
Communications No Cannot reach required range legally using 24GHz Wi-Fi
Storage and Data Yes Worst case analysis still within bandwidth
Software Yes Delay using MATLAB is less then human noticeable delay
Navigation Yes Previous work with AR Drone 20 demonstrated waypoint travel
GUI Software Yes NASA WorldWind capable of interfacing with Java
39
bull 3km range requirement will need to be reassessed with customer
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
Intro Project Description Feasibility Analysis Moving Ahead Conclusion
Conclusion
Areas of concern
bull 3km range requirement is large affects power mass and communication feasibility and the reason for its existence is unclear
bull Inertial sensor navigation introduces large error and will require extensive testing to understand ldquoreturn to homerdquo feasibility
Overall Project feasibility
The proposed project will be feasible if the range requirement can be reduced
40
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]
References 41
[1] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Conceptual Design Documentrdquo University of Colorado Department of Aerospace Engineering 30SEP2013
[2] Brennan Gentile Hillery Miekle Overcash Rivera Sissom Wiesman Zhu ldquoSIVAQ Project Definition Documentrdquo University of Colorado Department of Aerospace Engineering 23SEP2013
[3] ldquoTechnical Specifications State of the Art Technologyrdquo Parrot AR Drone 20 [httpardrone2parrotcomardrone-2specifications]
[4] Akos D M ldquoWhorsquos afraid of the spoofer GPSGNSS spoofing detection via automatic gain control (AGC)rdquo Navigation 59(4)281ndash290 2012
[5] ldquoCOA Notesrdquo 19SEP2013 [httpsrecuv-opscoloradoeduprojectsfaa_coawikiHow-to-Obtain-a-COA]
[6] Garrock ldquoWheel Antenna Mod ndash Significant Wifi Performance Upgraderdquo Parrot AR Drone amp AR Drone 20 Forum 18JUL2012 [httpforumparrotcomardroneenviewtopicphpid=6721]
[7] Parrot AR Drone amp AR Drone 20 Forum [httpforumparrotcomardroneenviewtopicphpid=6721]
[8] Verbatim USB Storage Website ldquo16GB - TUFF-N-TINYtrade USB Driverdquo Copyright copy2013 [httpwwwverbatimcomprodusb-driveseveryday-usb-drivestuff-n-tiny-sku-97168]
[9] ldquoPyPy Speed Centerrdquo [httpspeedpypyorg]
[10] Full Blown Hucker ldquoTU Delft ndash Search and Rescue with AR Drone 2rdquo MultiRotorForumscom OCT2012 [httpwwwmultirotorforumscomshowthreadphp9288-TU-Delft-96-Search-and-Rescue-with-AR-Drone-2amps=f93bdfa922cee6524313f08fe267be6800]
[11] Bristeau P J Callou F Vissiegravere D Peiti N ldquoThe Navigation and Control technology inside the ARDrone micro UAVrdquo [httpcasensmpfr~petitpapersifac11pjbpdf]
[12] Texas Instruments ldquoAM335x-PSP 04060008 Features and Performance Guiderdquo [httpprocessorswikiticomindexphpAM335x-PSP_04060008_Features_and_Performance_GuideEthernet_Driver]
[13] Levys ldquoARDrone AutoPylotrdquo [httphomewluedu~levyssoftwareardrone_autopylot]