Patent ID: 6608998
Filing Date: 2003-08-19
Classification: G01S

Abstract:
A method for reducing frequency-dependent bias effects in a fixed satellite-based ground-positioning receiver having the capability to receive both pseudorandom noise (PRN) encoded signals such as transmitted by GPS satellites, and frequency division multiple access (FDMA) signals such as transmitted by GLONASS satellites, said method comprising the steps of:obtaining pseudorange measurements from the PRN signals at times t0, t1, and t2; computing theoretical PRN satellite range measurements at times t0, t1, and t2; determining PRN satellite clock offsets at times t0, t1, and t2; deriving a PRN correction value at time t2 from said PRN pseudorange measurements, said theoretical PRN range measurements, and said PRN satellite clock offsets; obtaining FDMA pseudorange measurements (i) at time t0 and at a reference frequency fREF, (ii) at time t1 and at a first frequency f1, and (iii) at time t2 and at said reference frequency fREF; computing theoretical FDMA satellite range measurements at times t0, t1, and t2; determining FDMA satellite clock offsets at times t0, t1, and t2; and obtaining a bias correction value at time t2 for said first frequency f1 from said PRN correction value at time t2, said FDMA pseudorange measurements, said theoretical FDMA satellite range measurements, and said FDMA satellite clock offsets.