Patent ID: RE40642

Claim:
A method for identifying location of an object to be tracked, comprising: measuring data related to propagation time differences between signals transmitted from a plurality of GPS satellites and received at said object to be tracked, said data comprising code word phase measurements μ i for a satellite at a time t R , where μ i =γ i /T i C , and defined as time elapsed to time t R from the beginning of a code word in the signal from satellite i in which t R falls, y i being defined as the receiver code - time offset for satellite i and T i C being defined as the code period for satellite i at time t R in the signal received from satellite i, said code word phase measurements being simultaneously derived from the signals transmitted from said plurality of satellites and received at the object to be tracked; transmitting said data to a central station; and calculating at said central station the location of said object to be tracked based upon the transmitted data and data derived from at least one receiver apart from said object to be tracked receiving said signals from said plurality of satellites.