Patent ID: 8521028

Claim:
A method for obtaining GPS data from a GPS signal received at a plurality of antenna stations, each antenna station being connected to a common receiver station through an optical fiber link, the method involving a real time calibration of said optical fiber links and comprising the steps of: a) generating an optical signal at the receiver station and modulating the same according to an oscillating reference signal, thereby obtaining an optical reference signal; b) sending a portion of the optical reference signal to each one of the plurality of antenna stations through the corresponding optical fiber link; c) at each antenna station, modulating the optical reference signal according to the GPS signal received at said antenna station, thereby obtaining a twice modulated optical signal; d) sending the twice modulated optical signal from each antenna station to the receiver station through the corresponding optical fiber link; at the receiver station: e) extracting the GPS signal and the oscillating reference signal from the twice modulated optical signal received from each of said antenna stations; f) computing the real time calibration of said optical fiber links based on a phase comparison of the oscillating reference signals from different antenna stations; and g) processing the GPS signal from said antenna stations taking into account said real time calibration of the optical fiber links, thereby obtaining said GPS data.