Is there a way to track gps navigations already in a vehicle versus buying a separate gps tracking device?

They sell gps tracking devices for hundreds of dollars, but isn't there a way to just track the current gps navigation that is used in a car? Why have 2 devices if you can use the current one. Don't both use satelite to get locations etc?

A GPS device only needs to be a receiver to be a fully functional GPS Navigational System. Most GPS devices have only receiver capabilities.

To have a functional GPS Tracking System the GPS device must also be able to communicate with a tracking service information about its' location. Therefore the GPS device must be both a Receiver and a Transmitter.

You can find more information about GPS devices at http://www.sourcegps.com