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Automatic Target Recognition Using Passive Radar and a ...

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**1. **Automatic Target Recognition Using Passive Radar and a Coordinated Flight Model Lisa M. Ehrman
Advisor: Aaron D. Lanterman

**3. **What is Passive Radar? Active Radar
System has transmitter and receiver
Transmitter sends pulses which bounce off target
Determine target position and velocity from energy that bounces back Passive Radar
System only has a receiver
System exploits transmitters already available,
ie: TV, FM Radio used to determine target position and velocity

**4. **Why Use Passive Radar? Benefits
Covert
Cheap
Not as susceptible to bad weather or stealth
Lower frequencies ? RCS varies more slowly with time
Challenges
Transmitting signal not designed for target detection & tracking
Challenges have already been overcome by Howland, Herman, Lockheed Martin, …

**5. **Radar Cross Section (RCS) RCS Equation:

**6. **Coordinated Flight Model Goal
Estimate Aircraft Orientation from Position
Key Parameters
Heading:
Pitch:
Roll:
Assume Yaw = 0°

**7. **Modeling RCS 3) Use AREPS to Model Propagation Losses:
Between Transmitter and Aircraft
Between Aircraft and Receiver

**8. **Creating Noisy Profiles Problem
In Absence of Real Data, Simulate the Power Profile Arriving at the Receiver
Add White Gaussian Noise
Assume phase is equally likely everywhere in [0,2p]
Traces out a circle in the Complex Plane, whose radius is the RCS magnitude
Model the thermal noise as normally distributed white Gaussian noise, acting independently in the Real and Imaginary directions
Add the noise to the profile using:

**9. **Computing Noise Power Noise Figure Vs. Noise Power:

**10. **Identifying the Aircraft Use Loglikelihoods to Identify Aircraft Model
Rician Model Compares the Library of Profiles to the Simulated Profile at the Receiver
Treat each point in time as an independent sample of a process
Loglikelihood is given by
The aircraft with the largest loglikelihood is matched to the target

**11. **Geometries Tested Simple Scenarios
Straight and Level Flight
Banked Turn
Complex Scenario
Real Flight Profile*

**12. **Straight and Level Flight: Probability of Error Vs. Noise Figure

**13. **Straight and Level Flight: Power Profiles

**14. **Straight and Level Flight: Confusion Matrices Noise Figure = 35 dB, Noise Power = -166 dB
Noise Figure = 40 dB, Noise Power = -161 dB
Noise Figure = 45 dB, Noise Power = -156 dB

**15. **Banked-Turn Flight Profile: Probability of Error Vs. Noise Figure

**16. **Banked-Turn Flight Profile: Power Profiles

**17. **Banked-Turn Flight Profile: Confusion Matrices Noise Figure = 45 dB, Noise Power = -156 dB
Noise Figure = 50 dB, Noise Power = -151 dB
Noise Figure = 60 dB, Noise Power = -141 dB

**18. **F-15 Trajectory: 3-D

**19. **F-15 Trajectory : Top View

**20. **F-15 Trajectory, Real Angles: Probability of Error Vs. Noise Figure

**21. **F-15 Trajectory, Real Angles: Power Profiles

**22. **F-15 Trajectory, Real Angles: Confusion Matrices Noise Figure = 55 dB, Noise Power = -146 dB
Noise Figure = 60 dB, Noise Power = -141 dB
Noise Figure = 65 dB, Noise Power = -136 dB

**23. **F-15 Trajectory, Est. Angles: Probability of Error Vs. Noise Figure

**24. **F-15 Trajectory, Est. Angles: Power Profiles

**25. **F-15 Trajectory, Est. Angles: Confusion Matrices Noise Figure = 55 dB, Noise Power = -146 dB
Noise Figure = 60 dB, Noise Power = -141 dB
Noise Figure = 65 dB, Noise Power = -136 dB

**26. **Estimating Aircraft Heading

**27. **Estimating Aircraft Pitch

**28. **Estimating Aircraft Roll

**29. **Conclusions Performance Varies Greatly with SNR
If you can get SNR > 1, this is a viable approach
If you have trouble correctly identifying aircraft and SNR > 1, you probably need a more sophisticated means for estimating aircraft orientation

**30. **Future Work Finish the FISC Database, using more sophisticated techniques
Determine whether or not the out-of-band and direct-path interference can be accounted for in this manner
Determine impact of errors in position estimates

**31. **BACK-UP SLIDES

**32. **SYSTEM DESCRIPTION Transmitter:
GPS Location: 52°01’00” N, 05°03’00” E
Altitude (ASL): 375 m
Frequency: 100 MHz
Peak Power: 100 kW
Type: Omni-directional
Polarization: Horizontal
Receiver:
GPS Location: 52°06’36” N, 04°19’26” E
Altitude (ASL): 100 m
Direction: 320° (0°=N, 90°=E, 180°=S, 270°=W)

**33. **RECEIVER GAIN PATTERN