A backup form of local, ground-based GPS known as eLoran is being installed in some spots around the UK, hoping to keep some sort of shipping business continuing as usual should the satellite GPS systems get taken out by solar flares or North Korean laser satellites.
The Loran, or Long Range Navigation system, was originally developed back in WWII to safely steer ships. With all of today's shipping heavily dependent on GPS for steering and safety, the General Lighthouse Authorities has installed the upgraded eLoran system in seven ports around the UK to keep boats full of gadgets arriving safely in the event of a GPS outage or deliberate jamming attack.
Dover, Sheerness, Harwich and Felixstowe are among the places to let ships use this backup local location system now, although without governmental backing from overseas shippers, it's likely to remain a niche emergency alternative to GPS rather than a mainstream navigation option. [BBC]