A mobile GPS location system. The location system includes a mobile radio transceiver for transmitting a radio positioning signal and receiving a responsive radio system signal having a radio positioning system (RPS)-based time and position derived from the radio positioning signal; a mobile global positioning system (GPS) receiver; and a code range selector using the RPS-based time and position for selecting a code search range. The mobile GPS receiver uses the code search range for focusing a code phase search to a narrow range for rapidly acquiring a GPS signal. The RPS-based time and position are derived from a plurality of radio signal times-of-arrival (TOA)s determined by a plurality of system units from the radio positioning signal.