GPS spoofing and Totem ECDIS

According to Israeli marine electronics company TotemPlus, there has been considerable discussion following media reports of hackers jamming or spoofing GPS signals.

This practice, which was highlighted in The Motorship as long ago as the July/August 2012 issue, apparently allows terrorists to cause a ship to deviate from its planned course, and as a result to be hijacked. The threat was described as “a gaping hole in national security”.

Although the company believes this particular situation might be exaggerated, there is still a real risk, meaning precautions are needed. The company says that for users of its own Totem ECDIS, the risk is indeed minimal if the equipment is set up properly.

It says that monitoring the dead reckoning (DR), i.e. plotting based on course and speed, is an old and trusted method of sea navigation. The Totem ECDIS is able to continuously monitor gyro and speed log output in addition to GPS signals. If the distance between positions derived from GPS and DR is greater than a value set by the user – a 1-10 naut mile difference is recommended – an alarm will pop up. Future versions of the will incorporate a further alarm to warn of differences between Gyro and COG (GPS course over ground).

TotemPlus says once an alarm is raised, users should ascertain position using another method such as radar, from the ‘Tools\navigation Tools\Manual Fix’ menu option. If the GPS is found to be spoofed or unreliable, the primary position device can be switched to DR. The company further recommends that a ‘safe period’ be set, after which DR and GPS can be automatically synchronised. The ‘safe period’ means a long enough period in which normal DR and GPS differences are acceptable and can be accounted for.