direction finding presentation

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WPI MQP Group: Daniel Guerin - ECE Shane Jackson - Physics Jonathan Kelly - CS/ECE Phase Interferometry Direction Finding WPI Advisors: Ted Clancy Germano Iannacchione George Heineman Group 108 Staff: Chris Strus Lisa Basile Kelly McPhail

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Radio wawe direction finding methods

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  • WPI MQP Group:

    Daniel Guerin - ECE

    Shane Jackson - Physics

    Jonathan Kelly - CS/ECE

    Phase Interferometry Direction

    Finding

    WPI Advisors:

    Ted Clancy

    Germano Iannacchione

    George Heineman

    Group 108 Staff:

    Chris Strus

    Lisa Basile

    Kelly McPhail

    li17727Text BoxThis work is sponsored by the Department of the Air Force under Air Force Contract #FA8721-10-C-0007. Opinions, interpretations, conclusions, and recommendations are those of the authors and not necessarily endorsed by the United States Government.

    li17727Text BoxDISTRIBUTION STATEMENT A. Approved for public release. Distribution is unlimited.

  • Direction Finding - 2

    Group 108 10/01/12

    Project Goal

    Create a passive Direction Finding system for an airborne platform capable of determining the Angle of Arrival (AoA) in the azimuth plane.

    Display results in a real-time graphical interface

    Overview

    Specifications

    2.5 accuracy

    40 dB dynamic range

    90 field of view

    1 Hz update rate

    100 MHz bandwidth IF signal

    X Band Frequency (8-12 GHz)

    Secondary Objectives

    Track 3 beacons

    180 field of view

  • Direction Finding - 3

    Group 108 10/01/12

    Planned System

    Provided by Lincoln Laboratory Project Scope

  • Direction Finding - 4

    Group 108 10/01/12

    1. Phase Interferometry

    2. MATLAB Model

    3. Prototype System

    4. Summary

    Contents

  • Direction Finding - 5

    Group 108 10/01/12

    Passive Direction Finding

    Method Complexity Size Accuracy

    Time Difference of Arrival Medium

    Amplitude Comparison Low

    Phase Interferometry High

    Interferometer Geometry

    (Massa, OConnor, Silva, 2011)

    Scope of this project

  • Direction Finding - 6

    Group 108 10/01/12

    Phase Interferometry

  • Direction Finding - 7

    Group 108 10/01/12

    Phase Ambiguities

    Phase eclipsing causes ambiguous results due to antenna

    spacing and wavelength

  • Direction Finding - 8

    Group 108 10/01/12

    Phase Ambiguities

    Phase eclipsing causes ambiguous results due to antenna

    spacing and wavelength

    +2

    -2

    0

  • Direction Finding - 9

    Group 108 10/01/12

    Phase Ambiguities

    Phase eclipsing causes ambiguous results due to antenna

    spacing and wavelength

    +4

    +6

    +2

    -2

    -4

    -6

    0

  • Direction Finding - 10

    Group 108 10/01/12

    Resolving Ambiguities

    Utilize multiple antennas for disambiguation

    Compute Phase difference from Antenna 1 to 2

    Compute Phase difference from Antenna 1 to 3

    Compare possible angle solutions for common angle value

    Antenna Spacing selected based on RF input requirement to minimize ambiguities

    =10cm

    =21cm

  • Direction Finding - 11

    Group 108 10/01/12

    Resolving Ambiguities

    Adding a third antenna provides unambiguous result

    Possible angles from

    antennas 1 and 2

    Possible angles from

    antennas 1 and 3

  • Direction Finding - 12

    Group 108 10/01/12

    Resolving Ambiguities

    Adding a third antenna provides unambiguous result

    Possible angles from

    antennas 1 and 2

    Possible angles from

    antennas 1 and 3

  • Direction Finding - 13

    Group 108 10/01/12

    1. Phase Interferometry

    2. MATLAB Model

    3. Prototype System

    4. Summary

    Contents

  • Direction Finding - 14

    Group 108 10/01/12

    MATLAB Model

    Used to develop and test the direction finding algorithm

    Simulates every step of the physical system

    Pulsed wave generation, frequency down-converting, sampling waves

    All processing steps in the final system tested in model first

    Provided Hardware Project Scope

  • Direction Finding - 15

    Group 108 10/01/12

    MATLAB Model

  • Direction Finding - 16

    Group 108 10/01/12

    MATLAB Results

    True AoA (degrees)

    P = -40dBfs F = 12GHz D = 1km

    Absolute Angle Error

    An

    gle

    Err

    or

    (de

    gre

    es) Incorrect Ambiguity

    Angle

    Incorrect Ambiguity

    Angle

    Measured Angle vs. Actual Angle

    Worst Case Scenario

    Ca

    lcu

    late

    d A

    oA

    (d

    eg

    ree

    s) -90

    0

    90

    True AoA (degrees) 90 0

    An

    gle

    Err

    or(

    de

    gre

    es

    )

    -90 0 90 -45 45 0

    2.5

    5

    Primary AoA

    Secondary AoA

    Rare ambiguity errors can cause

    erroneous calculations

    Algorithm Performance

    Mean Error 0.097

    Mean Certainty 0.87

    Ambiguity Error 1.08%

  • Direction Finding - 17

    Group 108 10/01/12

    MATLAB Results

    Incorrect Ambiguity Angle

    Algorithm Performance

    Mean Error 0.097

    Mean Certainty 0.87

    Ambiguity Error 1.08%

  • Direction Finding - 18

    Group 108 10/01/12

    1. Phase Interferometry

    2. MATLAB Model

    3. Prototype System

    4. Summary

    Contents

  • Direction Finding - 19

    Group 108 10/01/12

    Prototype System

    Provided by Lincoln Laboratory Project Scope

    Third input channel not implemented due to hardware issues

    Three antenna mode tested with MATLAB inputs

  • Direction Finding - 20

    Group 108 10/01/12

    Prototype Results

    Strong agreement between verified model and C algorithm

    Processing time within specification

    Data transfer accounts for 99.7% of latency

    GUI demonstrated with simulated and captured data

  • Direction Finding - 21

    Group 108 10/01/12

    Real-Time Display GUI

  • Direction Finding - 22

    Group 108 10/01/12

    Real-Time Display GUI

    Disambiguated Emitter Indication

  • Direction Finding - 23

    Group 108 10/01/12

    Real-Time Display GUI

    Ambiguous Emitter Indication

  • Direction Finding - 24

    Group 108 10/01/12

    Real-Time Display GUI

    Detailed Emitter Information

  • Direction Finding - 25

    Group 108 10/01/12

    Real-Time Display GUI

    Angle Statistics

  • Direction Finding - 26

    Group 108 10/01/12

    Real-Time Display GUI

    Frequency Statistics

  • Direction Finding - 27

    Group 108 10/01/12

    Real-Time Display GUI

    Angle Certainty

  • Direction Finding - 28

    Group 108 10/01/12

    Real-Time Display Demo

  • Direction Finding - 29

    Group 108 10/01/12

    1. Phase Interferometry

    2. MATLAB Model

    3. Prototype System

    4. Summary

    Contents

  • Direction Finding - 30

    Group 108 10/01/12

    Performance

    Combine phase interferometry and amplitude comparison for two antenna solution

    Move real-time processing to FPGA

    Enhance tracking algorithm to reduce probability of false ambiguity selection

    Testing

    Test three channel operation with live data

    Verify operation with antennas connected

    Future Work

  • Direction Finding - 31

    Group 108 10/01/12

    Successfully met all primary requirements with simulated signals

    Extended field of view to 85

    Capable of identifying multiple emitters per batch

    Three channel operation verified with simulated data

    Two channel operation verified with live signal generator data

    Conclusion

  • Direction Finding - 32

    Group 108 10/01/12

    Emily Anesta

    Lisa Basile

    Ted Clancy

    Sarah Curry

    George Heineman

    Germano Iannacchione

    Kelly McPhail

    Christopher Strus

    Acknowledgements

  • Direction Finding - 33

    Group 108 10/01/12

    Resolving Phase

  • Direction Finding - 34

    Group 108 10/01/12

    Finding Optimal Antenna Separation

  • Direction Finding - 35

    Group 108 10/01/12

    GUI Sample for Two Channel Inputs