With GPS jamming a growing worry for UK shipping, engineers have successfully demonstrated the first system that can counter the navigational menace by switching seamlessly to a new type of shore-based ‘eLoran’ system.

In development since 2005, the ACCSEAS project used a system on the vessel THV Galatea in the seas off Harwich to show that the PNT (Positioning, Navigation and Timing) technology was resilient enough to withstand the worst case scenario of a ship suddenly losing all GPS signals.

In theory it would be possible to simply turn off a GPS system and switch on the powerful, longwave eLoran (eLOng RAnge Navigation), but in the middle of a busy shipping lane sea captains don’t necessarily realise what is happening to them quickly enough.

That delay can be dangerous not to mention troublesome for a shipping industry increasingly conscious of safety and the UN's International Maritime Organization (IMO) e-Navigation initiative. The new system switches automatically.

Until recently, problems with GPS were caused by natural phenomena such as solar interference or weather but recently GPS jamming from cheap devices sold from the Internet has become a major issue.

“If someone wanted to jam the Dover Strait they could do it,” comments Martin Bransby, Research & Radionavigation Manager at the General Lighthouse Authorities government agency.

According to Bransby, a major culprit was probably Bulgarian and Romanian truck drivers who used jammers to foil road toll systems in their home countries.

After loading their trucks to cross the channel they forget to turn the jammers off, causing potential problems for GPS in busy shipping lanes.

Given the number of foreign delivery trucks now on UK roads, this could also explain the surge in GPS jamming incidents along major motorways noted by surveys such as the Technology Strategy Board’s Sentinel Project.

“The more dependent we become on electronic systems, the more resilient they must be. Otherwise, we face a scenario where technology is actually reducing safety rather than enhancing it,” said Bransby.

“Demands on marine navigation are only getting tighter, yet electronic systems at sea are primitive compared to those used in air travel. This needs to change.”

The eLoran technology is a modern form of an old system, Loran-c (LOng RAnge Navigation), which has found a new lease of life after being seen as obsolete. Aircraft also used the older Loran.

The Dover area became the first in the world to start using eLoran for GPS backup, which will be extended to UK ports by 2019.