Britain urges ships to prepare for life without reliable GPS

Britain has warned shipowners that satellite can no longer be taken for granted in some of the world’s busiest shipping regions, urging crews to practise navigating without GPS as jamming and spoofing become increasingly widespread.

In a new Marine Guidance Note, MGN 719, the UK’s Maritime and Coastguard Agency (MCA) warns that interference across the Baltic, Black Sea, Middle East Gulf and parts of East Asia means satellite-derived positioning, and timing information can no longer be relied upon everywhere.

The warning extends well beyond electronic charts. The agency identifies a long list of potentially vulnerable equipment, including ECDIS, AIS, autopilots, dynamic positioning systems, radar, gyrocompasses and GMDSS communications equipment. Ashore, vessel traffic services, pilotage systems, port management platforms and automated logistics systems are also exposed.

The financial implications are considerable. Citing earlier UK government research, the MCA estimates that a seven-day GNSS outage could cost the British maritime economy £1.5bn ($2bn), including £1.3bn in port operations alone.

The guidance urges operators to identify precisely which systems depend on satellite-derived data, establish procedures for detecting interference and regularly drill crews in alternative methods. Radar fixing, visual bearings, celestial and dead reckoning are all recommended.

The notice follows growing evidence that satellite interference is becoming a routine operational hazard rather than an occasional inconvenience in conflict zones.

Maritime intelligence firm Windward’s latest figures show an average of 5,131 GPS jamming incidents a day during the third quarter, with more than 124,000 individual vessels affected.

Research published earlier this year by the Royal Institute of found that 14% of survey respondents had experienced an unsafe or unlawful situation resulting from GNSS interference.

In July, SplashTech reported on a government questionnaire, believed to have originated in Britain, asking ship operators whether their crews had conducted GNSS-denial drills, understood the vulnerabilities of interconnected bridge equipment and could operate ECDIS in dead-reckoning mode.

More recently, SplashTech reported how four tankers in the Black Sea had apparently broadcast positions placing them in Lima, Peru, more than 12,000 km away. Separate monitoring identified 1,702 impossible position jumps involving 379 vessels in the Gulf of Oman over a single week in September.

The UK is investing in a terrestrial backup through its enhanced Loran, or eLoran, programme, but the MCA’s latest guidance makes clear that technological alternatives will take time to become widely available.

Britain’s planned eLoran network is not expected to provide an initial timing capability until 2028, with full positioning and services targeted for 2030.