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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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