© David Last

LoodswezenCongress of Dutch Pilots

1 September 2008

Satellite Navigation Systems

– The Present Imperfect

Professor David Last

Picture: earthobservatory.nasa.gov//ewsroom/BlueMarble/

© David Last

USCGA Myst – First Enhanced Loranlive demonstration, 2007 Groton CT

Johnson, Swazek, Hartnett & Nichols, ‘Navigating harbors at high accuracywithout GPS – eLoran in the United States. ENC2007, paper 1049

© David Last

Picture: www.flickr.com/photos/guyburns/1878598347www.skyscrapercity.com/showthread.php?t=383984&page=3/

© David Last

Pictures: www.cargolaw.com/2003nightmare_tricolor.html, news.scotsman.com/topics.cfm?tid=703&id=2382003, www.cedre.fr/uk/spill/tricolor/tricolor.htm, news.bbc.co.uk/1/hi/uk/2620957.stm

© David Last

Picture: Wikipedia

eNavigation

• Single display• Data linked to shore• Clear, up-to-the minute• Charts and incidents

But GPS alone?

© David Last

GPS is perfect …

isn’t it?

Copyright: Dan Brown 2003

© David Last

Captain Fache plants abattery-sized GPS dot inLangdon’s pocket to trackhis location, wherever he is,accurate to 2 feet.It’s tiny!It’s amazingly accurate!It works indoors!

© David Last

What could possibly go wrong?

• Satellite and control system failures

• Solar flares

• Unintentional interference

• Intentional jamming

• Spoofing (and meaconing)

Well, for a start, let’s think about …

© David Last

Satellite and Control System Failures

Official announcement:"A significant GPS anomaly occurred on 1 Jan 04, beginning at approximately1833Z ... (which) … affected precise timing and navigation users over largeportions of Europe, Africa, Asia, Australia, and … North America … and resultedin the transmission of Hazardously Misleading Information."

Sources: Vogel, Macabiau & Suard, ‘Effect of a GPS Anomaly on Different GNSS Receivers’, ION GNSS 2005, Long Beach, CA, Sep 13-16, 2005, Hoppe & Walterfang, ‘Investigation of a GPS Satellite Problem with respect to DGPS and GPS users’, European Journal of Navigation, May 2004,www.lr.tudelft.nl/live/pagina.jsp?id=400f4487-ed8c-4274-95cb-ebc2afa7385e&lang=en

SVN23 clock failure

© David Last

Picture: Ashtech, Inc.

Picture: Kelvin Hughes Ltd.

Picture: europa.eu.int/comm/dgs/energy_transport/galileo/intro/index_en.htm

© David Last

Picture: Professor Durk van Willigen

• GPS satellite radiates 100W

• From 20,000km range

• Illuminates 38% of Earth

• eg Europe + Africa + Atlantic

© David Last

Solar flares

• Threat of unintentional interference and jamming• Risks can be reduced but not eliminated• Consequences severe for safety, economic damage• Tempting target for those hostile to the US• Can be spoofed to give misleading information• Need backup system in critical applications

Source: Clynch et al, ‘Multiple GPS RFI Sources in a Small California Harbor’, ION GPS02, Portland OR.

Dice is 1mW GPS jammer

Pictures: www.redferret.net/?p=7864

Observer, London, 29 Jan 2003

www.rin.org.uk

http://www.kenneke.com/plans.html#

© David Last

Jamming

Notice to Airmen (NOTAM): AC 555507 JUL 1100-1400 30000ft (A1063/02pt)08 JUL 0715-1015 30000ft (A1063/02pt)GPS Jamming Activity 5555N 00550W rad 320nm.

© David Last

Picture: www.flickr.com/photos/l23productions/1451697290/

© David Last

Picture: http://www.royalnavy.mod.uk/server/show/nav.2014

Ready to lose GPS!

© David Last

Spoofing

US Government Volpe Report, on Spoofing:

• Cause a … GPS receiver to lock onto legitimate-appearing false signals.

• Spoofing … will inject hazardously misleading information.

• (And, if not) … will …create significant … errors, and jam large areas …

• A spoofer also can defeat nearly all anti-jamming equipment.

And then there’s …

• Meaconing: receive, delay, and rebroadcast signals to confuse a user.

Picture: /www.imdb.com/title/tt0120347, www.naval-technology.com/projects/t23/

• British ship is sunk by Chinese in international waters.

• Clue is fake GPS signal controlled by techno-terrorist.

• Bond discovers GPS device - and wins the girl!

© David Last

© David Last

Spoofing

• Spoofing is an integrity problem.

• Civil receivers are bad at detecting spoofing.

• Detection needs another system, clever integration.

• Terrestrial back-up is the best defence.

© David Last

Pictures: Mitchell Narins, Federal Aviation Administration; Reelektronika bv

Enhanced Loran(eLoran)

• On earth, high-powered• Different from GPS! • Digital• 10m accuracy, precise time

© David Last

Picture: Mitchell Narins, US Federal Aviation Administration

© David Last

LoodswezenCongress of Dutch Pilots

1 September 2008

Satellite Navigation Systems

– The Present Imperfect

Professor David Last

Picture: earthobservatory.nasa.gov//ewsroom/BlueMarble/