Meteor ReceiverMeteor Receiver

Olajide DurosinmiHugh KinselKenny Mills

Austin PierceNick Stelmashenko

October 21, 2009

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Meteor Receiver OverviewMeteor Receiver Overview

• Receives radio signals reflected off of objects in the Earth’s atmosphere

• Provides sound when space object is detected

• Approximates direction and estimated speed of space objects

• Targets astronomy enthusiasts

• Costs $250 for prototype

Antenna

Receiver

Ionized Meteor Trail

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Meteor Receiver Objectives Meteor Receiver Objectives

Hardware• Receives a specific radio

frequency• Filters and amplifies the

given frequency• Reduces the amplified

signal to baseband• Converts the signal

from analog to digital for analysis

Software• Collects and stores the

digital data from the hardware

• Detects passing of a space object

• Outputs audible signal• Determines the

direction and speed of the objects

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Target Transmitter Frequency: 216.983 MHzTarget Transmitter Frequency: 216.983 MHz

• Naval Space Surveillance(NAVSPASUR) transmitter located in Texas

• Most powerful continuous wave transmitter on Earth• All circuit components based on 217 MHz

Lake Kickapoo, Texas Atlanta, Georgia

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Receiver Module

Antennas in Phased Array

Local OscillatorDemodulator

Analog to Digital Conversion

Filter and Low Noise Amplifiers

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Filter and Low Noise Amplifiers

Receiver ModuleLocal Oscillator

Demodulator

Analog to Digital Conversion

Antenna

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Yagi Dimensions Optimized for 217 MHzYagi Dimensions Optimized for 217 MHz

Symbol - Description

Length (λ) Length (m)

L1 - Reflector 0.487 0.673

L2 - Feed (Driver) 0.475 0.656

L2' - Gamma match 0.145 0.2

L3 - Director 0.41 0.567

S01 - Space between rear & L1

0.217 0.3

S12 - Space between L1 & L2

0.2 0.276

S23 - Space between L2 & L3

0.23 0.318

D1 - Diameter of elements

0.00919 0.0127

D2 - Diameter of Gamma match

0.00459 0.00635

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Estimated Antenna Specifications Simulated by NEC2 and Method of Moments MATLAB Code

Estimated Antenna Specifications Simulated by NEC2 and Method of Moments MATLAB Code

Number of elements 3

Center frequency (Fc) 217 MHz

Gain 9.2 dBd (11.35 dBi)

-3 dB beamwidth in the E-plane

58.88°

-3 dB beamwidth in the H-plane

75.18°

Front-to-back ratio in the E-Plane

12.1 dB

Impedance before match 35.2 + j14.2

Impedance after match 50 Ω

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Link Budget: Reason for AmplificationLink Budget: Reason for Amplification

Pr(d) = PtGtGrσλ2

(4π)2d4

Example Case: International Space Station

Pr = (767 kW)(104)(100.92)(100 m2)(1.382 m)2

(4π)2(1000 km)4

≈ 7.7 x 10-14 W = -101 dBm

• Radar equation used to estimate signal’s power level

• Multiple stages of amplification needed

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Filter and Low Noise Amplifiers

Receiver Module

Antennas in Phased Array

Local OscillatorDemodulator

Analog to Digital Conversion

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Filter and Low Noise Amplifier(LNA)Filter and Low Noise Amplifier(LNA)

• Filter designed with inductors and capacitors circuit

• Desired frequency centered in a narrow bandwidth

• Impedance of the filter is 50Ω (matching)

• MGA62563 LNA from Avago Technologies

• Cascading 2 LNA devices on a PCB to increase the gain, Av

• Expected gain, Av from LNA is 44dB

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Filter and LNA unitFilter and LNA unit

• Direct current (DC) blocking to limit DC flow

• Matching pads to reduce degrading of the signal

• Radio Frequency (RF) choke to limit RF noise

• Expected overall gain, Av, of unit is approximately 30dB

Power

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Filter and Low Noise Amplifiers

Receiver Module

Antennas in Phased Array

Local OscillatorDemodulator

Analog to Digital Conversion

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Local Oscillator DesignLocal Oscillator Design

Purpose Provide a reference signal for the receiver module

Design Frequency 434 MHz (217MHz x 2)

Design Considerations Low noise, Programmable

Design Choice ADF7012

Current Progress PCB designed, PCB and parts ordered and received

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Filter and Low Noise Amplifiers

Receiver Module

Antennas in Phased Array

Local OscillatorDemodulator

Analog to Digital Conversion

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Receiver Module DesignReceiver Module Design

Purpose Reduce the signal to baseband, Amplify the signal for DAQ

Design Considerations Low noise, Q and I outputs, Programmable gain

Design Choice AD8348

Inputs 434 MHz from oscillator, Amplified signal from LNAs

Outputs Q and I components of the mixed inputs

Current Progress Preliminary PCB designed

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Filter and Low Noise Amplifiers

Receiver Module

Antennas in Phased Array

Local OscillatorDemodulator

Analog to Digital Conversion

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Data AcquisitionData Acquisition

• NI USB-6251

– 16 analog inputs (1 MS/s)

– 2 analog outputs

– 24 digital I/O

– Signal Conditioning

• MATLAB Data Acquisition Toolbox

– Control outputs for variable gain amplifiers

– Store data in MATLAB for processing

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Line showing presence of CW transmitter

Data ProcessingData Processing

• Audacity

– Digital Audio Editor

– Quick Spectrum

• MATLAB

– Signal detection using STFT (Short-Time Fourier Transform)

– Spectrogram

– Estimate objects’ speed

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Filter and Low Noise Amplifiers

Receiver Module

Antennas in Phased Array

Local OscillatorDemodulator

Analog to Digital Conversion

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Phased ArrayPhased Array

• Purpose:

– Direction of arrival estimation

– Signal strength increase

• Four antennas/channels

– Identical hardware

• Processing with MATLAB

– Phase comparison in two planes

– Possibility of imaging

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Demonstration PlanDemonstration Plan

• Set up system components– Antennas, primary enclosure, laptop

• Listen for and successfully intercept echo from space object– Satellite, not meteor, due to predictability

• Process data– Calculate direction, position, radial velocity

– Present results to operators in real time

• Location: ECE rooftop

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Project ScheduleProject Schedule

• Test Local Oscillator circuit board October 23rd

• Order Receiver board and components October 23rd

• Order LNA board and components October 29th

• Test single system (Antenna to DAQ) November 10th

• Assemble additional systems November 15th

• Collect data for Matlab analysis November 20th

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Current Status of ProjectCurrent Status of Project

• Antenna prototype undergoing evaluation

• LNA and Filter design in progress

• Local oscillator ready for assembly and testing

• Receiver module designed

• Development of MATLAB software initiated

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Questions?

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Local OscillatorLocal Oscillator

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Local OscillatorLocal Oscillator

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DemodulatorDemodulator

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DemodulatorDemodulator

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DemodulatorDemodulator

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DemodulatorDemodulator