A wireless access point comprising a cellular receiver receives radio signals from a cellular base station. A cellular reference clock, synchronized to the cellular base station, is detected from the received radio signals. The detected cellular reference clock is utilized to stabilize a local access point clock for GNSS positioning. A clock difference between the local access point clock and the detected cellular reference clock is determined and the local access point clock may be adjusted accordingly. The adjusted local access point clock is utilized for clocking communications between the wireless access point and other communication devices. A time offset between the adjusted local access point clock and the detected cellular reference clock is provided to a remote location server. The remote location server retrieves time offset information from wireless access points served by the cellular base station so as to determine relative distances among the wireless access points.