Patent ID: 8085201

Claim:
A system for determining position utilizing signals of opportunity transmitted by at least three transmitters with known locations, the system comprising: a base receiver with a clock and a known position that calculates ranges to at least three of the transmitters and samples the signals of opportunity, time tags the signal samples with a time of receipt, a time of transmission or both and sends respective series of the time-tagged signal samples over a communications network; one or more remote receivers that receive information over the communications network, each remote receiver saving and time-tagging samples of signal segments of the signals of opportunity, correlating the time-tagged series of signal samples received over the communications network with the saved time-tagged samples of signal segments, determining for each of the at least three transmitters an associated time offset as a difference in the time of receipt at the remote receiver and either or both of the time of transmission by the transmitter or the time of receipt at the base receiver, and determining a position by determining pseudoranges to the at least three transmitters based on the time offsets.