Patent ID: 7340259

Claim:
A system for locating a wireless communications radio transmitter configured to emit radio frequency (RF) transmissions of digital signals on voice/traffic and control channels in accordance with a prescribed air-interface specification, comprising: first and second sensor stations, each of said sensor stations having an antenna and receiver configured to receive RF voice/traffic and control channel transmissions from the wireless communications radio transmitter, and an analog-to-digital converter mechanism configured to create digitized time tagged sampled signals representing a received RF transmission of interest; a signal replica unit at each of said first and second sensor stations for providing a signal replica comprising a series of data values matching a portion of the received transmission, wherein said signal replica is provided using locally pre-stored information content known to be contained in the received RF transmission, said information content being stored in a local replica storage unit associated with each signal replica unit, the information stored in each local replica storage unit including a sequence of bits known a priori to be contained in the RF voice/traffic channel transmissions from the wireless communications radio transmitter, and bit strings known a priori to be contained in the RF control channel transmissions from the wireless communications radio transmitter; a modulator associated with each signal replica unit at each of said first and second sensor stations, each said modulator configured to receive from the associated replica storage unit and to modulate pre-stored sample replica data in accordance with the prescribed air-interface specification to produce a locally-derived matched replica signal; and a correlation processor at each of said sensor stations, said correlation processor configured to correlate the digitized sampled signals representing the received RF transmission with said locally-derived matched replica signal to determine a time of arrival measurement for the received RF transmission.