With the rise in active tracking systems for motorcycles, though, I noted this story with great interest:
Car Thieves Using GPS 'Jammers'
Criminal gangs have begun using GPS "jammers" imported from China to help them steal expensive cars and lorries carrying valuable loads – and there are fears that terrorists could use more powerful versions to disrupt air traffic, a conference in London will hear on Tuesday. The "jammers" put out radio signals at the same frequency at the Global Positioning System (GPS) satellites, overwhelming the timing signal that in-car devices use to plot their position. That means a tracker device built into a lorry with a valuable load, or a car with an anti-theft GPS device which should report its position if stolen, cannot distinguish the correct GPS signal...
Such systems have been found in the hands of criminals arrested by police over the past 18 months, said Cockshott. The jammers could be built by a competent electronics expert, though the gangs appear to prefer to import them from Chinese makers in Shenzhen.
Sure enough, a two second search over on Alibaba shows dozens of these things available - mobile versions are going for about $30-50 a pop. Product specs show options for blockage ranging from a few meters to 1000mw long range versions that can supposedly block everything up to 30 meters.
This is not good, because it won't be long before this migrates over to motorcycle theft, too.
Wired magazine covered this story as well, and is quick to note that RF-based trackers (Like LoJack) aren't affected by these GPS jammers, but one can guess that RF frequencies are next on the hitlist.
There's a couple of demos over on youtube, natch: