GPS Jamming and the Impact on Maritime Navigation

GPS Jamming and the Impact on Maritime Navigation Alan Grant, Paul Williams, Nick Ward and Sally Basker General Lighthouse Authorities of the United Kingdom and Ireland GNSS Vulnerabilities and solutions conference, Croatia, 8 th September 2008

GPS Jamming Trial 2 -4 th April 2008 from Flamborough Head on the East Coast of the United Kingdom. Jamming units provided and operated by Defence Science and Technology Laboratories (DSTL) Coverage area of the GPS jamming unit at 25 m above ground level on maximum power of 1. 58 W ERP. (Image courtesy of DSTL)

Elements under review Effect of GPS jamming on safe navigation Aids to Navigation (Ato. N) § e. Loran § Differential GPS § AIS as an Ato. N On Ship § Navigation systems § Situational awareness On Shore § Vessel Traffic Management/Services On People § Safe navigation

e. Loran receiver had integrated GPS receiver and could calculate its position using: • Calibrated e. Loran • ASF corrected e. Loran • Stand-alone Loran • Differential GPS (using Eurofix) • Stand-alone GPS Map showing the Loran stations used in the position solution. Loran v DGPS positions shows a Loran accuracy of 8. 1 m(95%).

e. Loran Reported position from e. Loran receiver operating in Eurofix corrected GPS mode during control run with Calibrated e. Loran mode with jamming enabled no jamming

Differential GPS The GLAs operate 14 DGPS stations

Synchronised Lights Synchronised lights simulating a port approach Lights use GPS as a common timing source

Ship systems GPS reported position is inland 22 km away from true position (e. Loran). e. Loran Position GPS Positions plotted using GPRMC NMEA data from run without jamming Erroneous reported positions as effect of jamming signal is observed. Colours indicate reported speed: blue <15 knts, yellow< 50 knts, orange <100 knots and red >100 knts

Effect on Ship & Shore The effect of GPS jamming on AIS was observed by: § NLV Pole Star’s AIS alarmed when GPS was lost. §Without GPS it could not provide a range or bearing to surrounding vessels or Ato. Ns. §Some AIS returns included erroneous positions.

People NLV Pole Star’s crew were able to navigate safely during GPS outage. However, it should be noted: § Vessel’s crew had advance knowledge § Parallel indexing on Radar § Switched ECDIS screen off Severity of GPS denial depends on: § Ability of crew to use traditional means § Availability of traditional means During entry and exit of the jamming region system alarms sounded for around 5 minutes.

Conclusions The main conclusion from this trial is that GPS service denial has a significant impact on maritime safety! On people ships Aids-to-Navigation e. Loran shore was unaffected by GPS jamming People are conditioned tocan expect excellent GPS Navigation, situational awareness, chart stabilisation and may DSC emergency DGPS Vessel reference Traffic Services/Management stations be jammed (VTS) and marine theperformance. impact image will result be confused in the as communications will be significantly affected ifhigh-velocities they are over based on GPS. absence AIS demonstrated information of DGPS anwith accuracy corrections erroneous of 8. 1 m and positions integrity (95%) and information aconflicts large with the Loss of familiarity with alternative methods of navigation or situational awareness geographical radar information. area may make a significant impact on safety and security. Vessels with integrated bridge systems (autopilot) could, depending on the Can be used to detect GPS errors and provide an independent position, system design, see the vessel’s course and heading change informing AIS Further navigation used study as and an istiming Ato. N needed information to broadcast determine (PNT) incorrect how to VTS maritime information; operators systems. will without respond. In this trial, despite themay fact that the Pole Star’s crew was forewarned, problems the watch-keeper. were experienced with the ECDIS. Synchronised With e-Navigation, lightsthe may combination not be synchronised of GPS, Galileo and e. Loran will provide When experiencing jamming, navigational safety is dependent onerror mariners’ robust and resilient PNT in can order to reduce the impact of be human and to The number of alarms that sound on the bridge can distracting. abilities to that GPS is being denied and to operate improve therecognise safety, security andservice protection of the marine environment. Moving to other increase in bridge workload. effectively usingnavigation alternativetechniquescan (e. g. cause radaran parallel-indexing). Increased of ECDIS will increase the announcement attendant risks. on their use of e. Loran. The GLAs use welcome the recent US policy

Thank you The authors’ would like to thank: § The crew of NLV Pole Star for their patience and assistance; § Maritime and Coast Guard Agency for their support; and § DSTL for providing and operating the GPS jamming units. Contact Details Dr Alan Grant, E-mail: alan. grant@thls. org, Telephone: +44 (0)1255 245141