Jammer Acquisition with GPS Exploration and Reconnaissance

Adrien Perkins James Spicer, Louis Dressel, Mark James, and Yu-Hsuan Chen

S C P N T P R E S E N TAT I O N

JÄGER

2

NextGen Airspace • Increasing use of GPS •! Need reliable signal during landing

•!Motivation

3

Newark Int’l Airport Example •  personal privacy device jamming

•  Need to locate and disable jammer quickly

• Motivation

4

Requirements and Simplifications •  Requirements

!  Quickly determine location of jamming device !  Navigate in a GPS denied environment !  Use only a single vehicle !  Pinpoint location

•  Initial Simplifications !  Stationary jammer !  Single jammer !  Constant jamming

• Motivation

5

Jammer Detection • Independent of GPS •! Bearing to jammer

!! Signal strength + heading !! Directional antenna + magnetometer

•! Multicopter vs. Plane !! Take measurements at fixed points

•!Methodology

strainsecuritysystems.squarespace.com

6

Path Planning • Represent problems as 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

•! Onboard computer actively communicating with flight computer

•!Methodology

Computer Flight Computer

7

Positioning •!Methodology

Hardened GPS

Signals of Opportunity

wifi

Digital TV

3G / 4G Cell Network

•! Alternate Position Navigation and Time (APNT)

•! Automatic Dependent Surveillance – Broadcast (ADS-B)

•! Universal Access Transceiver (UAT)

•! 1090 •! Distance Measuring Equipment

(DME)

•• Alternate Position Navigation and Alternate Position Navigation and Alternate Position Navigation and Alternate Position Navigation and Alternate Position Navigation and Alternate Position Navigation and Aviation Signals

8

Aviation Signals • Possible Signals

!! Automatic Dependent Surveillance – Broadcast (ADS-B) ›! Universal Access Transceiver (UAT) and 1090

!! Distance Measuring Equipment (DME) •! Initial testing with UAT signals •! Leverage known altitude from barometer

•!Methodology

9

System Diagram

•! All communication through autopilot •! Each system is completely

independent and modular !! Each has own power source

•!System Design

Weight: 2 kg Power: 12 W

Weight: 0.5 kg Power: 8 W

10

Vehicle Selection •! Target Performance

!! 20 minute flight !! 4 kg payload

•! DJI S1000 “Spreading Wings” Octocopter !! Frame Weight: 4.2 kg !! Max Takeoff Weight: 11.0 kg

•! Power !! Max of 4000 W !! 1.5 kg battery payload

•!System Design

11

Path Planning • Two way communication with Autopilot •! Hunt Mode for autopilot

!! Waits for commands from outside source !! Reports completion of maneuvers

•! Ground station for testing

•!System Integration

Computer Flight Computer

12

Path Planning •!System Integration

vehicle autopilot Path planning

Ground station

Safety pilot

Not Human

Position

Path planning to human

Command Command execution

1 – Path planning to human

13

Path Planning •!System Integration

vehicle autopilot Path planning

Ground station

Safety pilot

Not Human

Path planning to human 1

Human generated commands

Command Command execution

2 – Human generated commands

14

Path Planning •!System Integration

vehicle autopilot Path planning

Ground station

Safety pilot

Not Human

Path planning to human 1

2

Position

Command Command execution

Full integration and automation 3 – Full integration and automation

15

APNT Electromagnetic Interference (EMI) • 2 sources of interference onboard

!! Telemetry antenna at 915 MHz !! Computer at 1.575 GHz

•!System Integration

GPS signal before shielding (16 dB peak)

16

APNT Electromagnetic Interference (EMI) • System Integration

17

APNT Electromagnetic Interference (EMI) •!System Integration

Before shielding (16 dB peak)

After shielding (-2 dB peak)

18

Flight Testing • Split series of flights by hardware being flown

Series 1: •! Pixhawk

Series 2: •! Pixhawk + APNT

Series 3: •! Pixhawk + Path Planning

Series 4: •! Pixhawk + APNT

+ Path Planning

•!Testing

19

Autopilot Only •  Test vehicle performance

!  Stability

Weight simulation

• Testing

Tethered Testing

20

UAT Ground Test • Static and dynamic tests

•!Testing

12 km

40 km

21

APNT Ranging • Results

0 100 200 300 400 500 600 700 min = 39656

+59

+118

+177

+235 Pseudorange from San Jose

Pseu

dora

nge(

m)

0 100 200 300 400 500 600 700 min = 11262

+73

+146

+219

+292 Pseudorange from Woodside

Pseu

dora

nge(

m)

UAT GPS

22

Ranging • Results

20 40 60 80 100 120 10 -3

10 -2

Histo of Pseudorange from San Jose, mean=76.2575m, std=11.6779m

80 100 120 140 160 180 200 10 -3

10 -2

Histo of Pseudorange from Woodside, mean=138.5428m, std=12.6833m

Pseudorange Error Gaussian Fit

Pseudorange Error Gaussian Fit

23

Static • Results

GPS

UAT

-122.183 -122.1825 -122.182 -122.1815 -122.181 37.4308

37.431

37.4312

37.4314

37.4316

37.4318

37.432

37.4322

37.4324

37.4326

longtitude(degree)

latti

tude

(deg

ree)

24

Accuracy • Results

25

Dynamic • Results

GPS

UAT

-122.183 -122.1825 -122.182 -122.1815 -122.181

37.431

37.4315

37.432

37.4325

longtitude(degree)

latti

tude

(deg

ree)

26

Flight Testing •! APNT

!! Constant altitude !! Loiter at each vertex (static) !! Dynamic flight

•! Jammer Acquisition !! Wifi router to mimic jammer

•!Testing

Wifi

27

Future Work •  Flight testing of APNT at Camp Roberts

•  Continued path planning Integration

•  Jammer acquisition testing

•  Hardened GPS vs various signals of opportunity !  Explore the options

• Future

Questions?