Christopher Morin, Technical Director

US Air Force, 746th Test Squadron

Holloman AFB New Mexico USA

christopher.morin@holloman.af.mil

Delivering Reference Truth in a GPS-denied Environment

Distribution Statement A Approved for public release: distribution is

unlimited. PA #: 96ABW-2012-0490

This presentation is for information only. No U.S. Government commitment to sell, loan, lease, co-develop or co-produce defense articles or services is implied or intended. Where specific trade or

product names are identified, this does not constitute an US Air Force endorsement.

Opinions, interpretations, conclusions and recommendations are those of the author and are not necessarily endorsed by the US Air Force

Surviving without GPS

USAF 746th Test Squadron

GPS Threats to the Civil Sector

Civil Solutions to GPS Denial

Delivering Reference Truth

Questions

Agenda

Surviving without GPS

USAF 746th Test Squadron

2009 NJ Turnpike: http://www.economist.com/node/18304246

Civil GPS Denial

Commercially Available Civil GPS Jammers

Probably more like 30W

Probably more like 7W

Commercially Available Military GPS Jammer

1W GPS Jammer on Parliament House 100ft AGL

J/S dB No P(Y) Tracking 54 No C/A Tracking 44 No P(Y) Acquisition 34 No C/A Acquisition 24

1W GPS Jammer on Parliament House 1000 ft AGL

J/S dB No P(Y) Tracking 54 No C/A Tracking 44 No P(Y) Acquisition 34 No C/A Acquisition 24

10W GPS Jammer on Parliament House 100ft AGL

J/S dB No P(Y) Tracking 54 No C/A Tracking 44 No P(Y) Acquisition 34 No C/A Acquisition 24

10W GPS Jammer on Parliament House 1000 ft AGL

J/S dB No P(Y) Tracking 54 No C/A Tracking 44 No P(Y) Acquisition 34 No C/A Acquisition 24

1W GPS Jammer on Sydney Harbour Bridge 100ft AGL

J/S dB No P(Y) Tracking 54 No C/A Tracking 44 No P(Y) Acquisition 34 No C/A Acquisition 24

1W GPS Jammer on Sydney Harbour Bridge 1000 ft AGL

J/S dB No P(Y) Tracking 54 No C/A Tracking 44 No P(Y) Acquisition 34 No C/A Acquisition 24

10W GPS Jammer on Sydney Harbour Bridge 100ft AGL

J/S dB No P(Y) Tracking 54 No C/A Tracking 44 No P(Y) Acquisition 34 No C/A Acquisition 24

10W GPS Jammer on Sydney Harbour Bridge 1000 ft AGL

J/S dB No P(Y) Tracking 54 No C/A Tracking 44 No P(Y) Acquisition 34 No C/A Acquisition 24

Use Controlled Reception Pattern Antennas (CRPA) Null in directions of strong interference Few in civilian market = expensive More protection than choke rings, but still limited

Choke Ring / Horizon Ring Nulling Antennas

Attenuate signals entering antenna close to the horizon Typical: ~15 dB attenuation of signals at 90 (horizon)

Inexpensive, but limited protection

Use Terrain or RF Blocking/Absorbing Material To Mask Jamming

Place GPS receive antennas on ground or in a depression No cost, excellent protection from ground based interference sources

Use metal or other conductive materials to block interference Use Eccosorb® or other RF absorbing materials to attenuate interference

Civil Solutions to GPS Denial

Backup clocks

Use GPS-disciplined clocks

Use alternate/redundant time truth

Implement software/firmware checks with meaningful warnings

Use software to monitor changes in J/S

Use redundant antennas for integrity

Test implementations for time and/or position sensitivity Unreasonably large position changes or accelerations

Out of bounds calculated responses such as power draw or machine speed

Errors related to time and position sensitivities should warn the user of possible GPS-denial as a source of error

Civil Solutions to GPS Denial

Military Application of GPS MQ-9 Reconnoiters area in high

J/S EW environment

B-2 penetrates enemy IADS to

deliver MOP on target in high J/S

EW environment

Adversary attempts to protect high value assets with

mix of medium-power, man portable GPS jammers

and vehicle mounted high-power GPS jammers.

Recreating a NAVWAR Environment

Phoenix

ABQ

El Paso

Notes:

- Area controlled by Albuquerque ARTCC

- GPS L1 and L2 test, BB/PCW/SCW

- During Albuquerque non-peak times (2000L-0600L)

- Civilian receivers affected in entire area shown

HAFB

Stallion AAF

J/S dB No P(Y) Tracking 54 No C/A Tracking 44 No P(Y) Acquisition 34 No C/A Acquisition 24

25K MSL L1

50 NM

TSPI vs. Reference TSPI:

Provides time, space & position information (TSPI) No rigorous accuracy verification High uncertainty in produced data

Reference: Truth in time, position, velocity, acceleration and

attitude against which another system is measured Verified at the component level and as a system

against other known reference systems (Test Track, 3-axis tables, historical data)

Resolution of inconsistencies between test results and theoretical performance

Uncertainty significantly reduced

Reference Truth

“Truth”

Reference

TSPI

UUT – Unknown

Performance

746 TS Reference System Accuracy

GPS - original 16m SEP GPS Accuracy Improvement

Initiative

Relative Nav Next-Gen Systems

CIRIS

CHAPS

CRS

CRS evolved UHARS (Objective)

1 nmi/hr

0.8 nmi/hr

0.4 nmi/hr

0.1 nmi/hr

0.01

0.10

1.00

10.00

100.00

1000.00

10000.00

1985 1990 1995 2000 2005 2010 2015 2020

Ho

rizo

nta

l P

osit

ion

Err

or,

1 H

r (m

)

Year

746 TS Reference vs. Systems Under Test

GPS Solutions

CIGTF Reference - Evolving

Inertial Only, CEP, 1 Hr

Ground Transceivers

Ultra High Accuracy Reference System (UHARS)

Accuracy

Threshold:

Position: 10 cm/axis

Velocity: 0.005 m/s

Objective:

Position: 5 cm/axis

Velocity: 0.001 m/s

Honeywell Enhanced EGI High-performance Inertial Sensors Advanced Digital GPS Receiver Digital Antenna Electronics Interface

Lockheed G-STAR Antenna Electronics 7-element ADAP antenna 6 simultaneous L1 & L2 nulls 8 concurrent L1 & L2 beam forms

Non-GPS Based Positioning System (Locata LocataNet®)

16-site LocataLite network GPS-disciplined atomic clock synchronizes LocataNet

master to GPS time

UHARS Key Components

Military Community: Warfighters must operate in a GPS-denied environment Reference Truth must be provided in GPS-denied environments...

unique & revolutionary tools were integrated to make this possible.

Civilian Community: GPS is vulnerable to denial Critical systems depend on GPS, what is the consequence when

denied? Take steps to mitigate consequences

Summary

Questions