Ships may be moving away from using Global Positioning System (GPS) navigation and towards a simpler, more old school technology, in order to avoid cyber security threats.

GPS and similar technologies that are used worldwide work by sending and receiving satellite signals, which can be easily jammed by hackers. If this happens and the crew finds themselves without a navigation system, ships face the possibility of running aground or into other ships.

This is particularly true in busy shipping lanes such as the English Channel, where more than 500 ships travel each day. Given the level of use, with an estimated 90% of worldwide trade transported at sea, the potential risk is high if GPS systems are breached.

In order to counter this, a number of countries are working on a radio-based navigation system, called eLoran, based on Loran, the decades-old Long Range Navigation technology. The developers of eLoran argue that the signals from their system are 1.3 million times stronger than GPS, and therefore significantly harder to jam.

Head of safety management at P&O Ferries, Grant Laversuch, told Reuters that there has grown to be a dependence on GPS systems, and the introduction of a secondary backup system would be positive. He said: ‘Good navigation is about cross-checking navigation systems, and at better way than having two independent electronic systems?’

A number of high profile GPS issues have cropped up in the past few years. South Korean shipping vessels were forced to return to port after their signals were jammed, supposedly by North Korean hackers. The U.S. Coast Guard reported interference in 2014 and 2015, and a cyber-attack on AP Moller-Maersk in June this year made headlines worldwide.

Support for eLoran is high among governments, given the threat to national security, but infrastructure costs have so far delayed progress. However, South Korean government officials have made plans to test eLoran at three sites by 2019, and the U.S. House of Representatives has passed a bill allowing eLoran technology to go ahead, meaning it now only needs to pass through the Senate.