With GPS jamming a growing worry for UK shipping, a new device seamlessly switches systems to counter the navigational menace. 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, reports PC Advisor. 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.