The GPS may work, however, a simple hockey puck is a better and more reliable option in my opinion.
The GPS is used for location based scanning. Allows the GPS to trigger turning on and off Sytems as you drive around. This is based upon the transmitter location (Lat & Long) being picked up in the Master Database download and/or you can enter transmitter location for your Favorite List not copied from the Master Database.
The scanner also gives you a range or distance from the transmitter before the scanner turns off or on a Department or System.