Patent ID: 6198430
Filing Date: 2001-03-06
Classification: G01S

Abstract:
A method of generating a differentially-corrected divergence-free carrier-smoothed pseudorange residual in a differential global positioning system, the method comprising:tracking at a dual frequency base station a first GPS signal, having a first frequency, from a first satellite;tracking at the base station a second GPS signal, having a second frequency, from the first satellite;determining at the base station a first pseudorange measurement .rho..sub.1.sup.B from the tracked first GPS signal;determining at the base station a first carrier phase measurement .phi..sub.1.sup.B from the tracked first GPS signal;determining at the base station a second carrier phase measurement .phi..sub.2.sup.B from the tracked second GPS signal;calculating at the base station a phase difference .DELTA..phi..sup.B between the first carrier phase measurement .phi..sub.1.sup.B and the second carrier phase measurement .phi..sub.2.sup.B ;calculating at the base station a first divergence-free carrier-smoothed pseudorange measurement .PSI..sub.1.sup.B from the first pseudorange measurement .rho..sub.1.sup.B, the first carrier phase measurement .phi..sub.1.sup.B, and the phase difference .DELTA..phi..sup.B ;deriving at the base station a differential correction from the first divergence-free carrier-smoothed pseudorange measurement .PSI..sub.1.sup.B ;providing the differential correction derived from the first divergence-free carrier-smoothed pseudorange measurement .PSI..sub.1.sup.B to a remote GPS receiver;providing the first carrier phase measurement .phi..sub.1.sup.B and the second carrier phase measurement .phi..sub.2.sup.B or the phase difference .DELTA..phi..sup.B to the remote GPS receiver; andcalculating at the remote GPS receiver the differentially-corrected divergence-free carrier smoothed-pseudorange residual.