JAGERJammer Acquisition with GPS Exploration and Reconnaissance

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Adrien Perkins

Stanford University

UAV bases system to help improve safety of nextgen airspace Autonomous rapid localization of GPS jammer

GPS denied navigation capabilities

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Overview

Path Planning

Partially observable Markov decision process (POMDP)

Grid-based, offline solution to a probabilistic model of sensor and vehicle motion

Based on real-time signal measurements and current belief of sensor location, take action that localizes the jammer in the shortest amount of time

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Our Solution

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Our Solution

GPS Denied Navigation

Hardened GPS

• RFI resistance

• Multi-frequency

• Multi-constellation

Signals of Opportunity

• Wifi

• Cell network

• Digital TV

Vision Systems

• Stereo vision

• Monocular vision

• Infrared

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System Diagram

Requirements 20 minute flight 4 kg payload

DJI S1000 “Spreading Wings” Octocopter Frame weight: 4.2 kg Max takeoff weight: 11.0 kg Features

› Carbon fiber frame

› Retractable landing gear

Flight Batteries 2x 8800mAh 6S 30C Lipo 1.22 kg each

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The Vehicle

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Electromagnetic Interference

Single directional antenna 9 dBi gain

60-degree beamwidth

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Mobile Sensor

Bearing calculation methods Max

Cross Correlation (CC)

-3dB Point (Max3)

Bearing Calculation

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Measurement Classification

Close < 0.58*h

Ideal

Far > 200m

Far

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Gain Patterns

250m 300m

Close

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Gain Patterns

7m

Ideal

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Gain Patterns

26.6m

Error Distribution Overall and ideal Gaussian

Near is noise

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Bearing Method Performance

Std Dev (°) Max CC Max3

Overall 26.2 27.9 21.9

Ideal 16.3 13.7 13.2

Close 46.0 44.2 37.7

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Bearing Method Performance

Patterns aren’t perfect Imperfections problematic for Max

Max3 “smoothing”

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Bearing Method Performance

True Bearing 91.7°

Max 116°

CC 93°

Max3 93°

88 different gain patterns produced

Range from Signal Strength

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> -65 > -70 > -75 > -80 < -80

RSSI Value (dBm)

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Experiment Overview

Joint Interagency Field Experimentation (JIFX)Camp Roberts, CA

WiFi as GPS proxy

Directional antenna for bearing

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Experiment Overview

Pilot

GS

Operator

Safety

OfficerObservations

Greedy Approach

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POMDP Approach

Sensing Rotation based sensing Characterized performance Accurately determine bearing

Developed path planning POMDP promising performance Developing new filters

Future work GPS jammer localization SLAM implementation Alternate antenna configurations

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Conclusion

Thank youQuestions?

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