Here’s a gadget from Chinavasion that simply blocks any GPS tracking device signal in a 2-4 meter coverage area.
The whole idea is the device gets plugged into the cigarette lighter of the car and soon after it starts jamming GPS signals in a broadcasting range of 1450 to 1600Mhz.
This jammer is powered by the 12V adapter from your car.
The specifications of the jammer are:
Though the jammer may not be legal to use is some of the countries, Chinavasion will launch the device very soon.