Abstract: A system and method for determining whether a wireless device has transmitted one or more forged radio frequency (“RF”) measurements. A first set of signals from a plurality of RF sources may be received at a wireless device and transmitted to a location determining system. The location determining system may receive a second set of signals from the plurality of RF sources during substantially the same time period and frequency range. The location determining system may compare information from the second set of signals with information from the first set of signals. Alternatively, the location determining system may determine a location of the wireless device as a function of the first set of signals and compare information from the second set of signals with the determined location.