Do two (or more) apps using GPS share the same location data stream?
In iOS, Location Services sits between all the location radios (cellular tower info, nearest wifi, GPS) and the apps, and caches the fused results between getting new information from those radios at a rate determined by the OS for decent battery life versus requested accuracy.  Apps never "control" or talk to the GPS hardware or OS driver directly.  The location information an app gets is time-stamped, so an app can check to see if it's old info or not.