You can fool a GPS tracking system by creating a signal that overpowers the signal coming into the system or by covering the antennae on the unit with a metal foil. Both of these methods cause the GPS collector not to accept and transmit indicators.
Creating a signal that overpowers the incoming signal is commonly referred to as jamming the signal. This prevents the GPS system from getting the signal, thus it can not record any geographic data. Prior to attempting this method, it is crucial to find out if the systems for jamming the signal are allowed in your area. The second method is to cover the antennae with metal foil. Locate the device in the vehicle, find the antennae and then wrap it with metal foil.