Real Time Precise Absolute Position Estimation of GEO Satellites using GPS

摘要

In this paper, the navigation signals (pseudorange and carrier phase measurements) from GPS are used to kinematically estimate the absolute position of a Geosynchronous Earth Orbit (GEO) satellite. The signals from GPS satellites, on the opposite side of the earth with respect to the GEO satellite, are acquired for extracting GPS observables which are used to estimate the precise position of a satellite in near real time. The GPS satellite navigation file, from Scripps Orbit and Permanent Array Centre (SOPAC) website, is used for starting epoch of 01-01-2016 00:00 UT. The observables are then generated for a Geostationary-Earth-Orbit satellite at an altitude of 35,793.4 km. The absolute position is estimated using pseudorange measurements. The 3 sigma errors obtained are [3.4547, 15.7617, 1.4324] m in ECEF frame. This estimated absolute position is then smoothened with the time- differenced carrier phase measurements. The Kalman filter gains are computed in near real time. The smoothened 3 sigma errors obtained are [1.4015, 7.3807, 0.6158] m in ECEF frame, thus showing improved estimated absolute position accuracy. The efficacy of the proposed scheme is also proven by the Monte Carlo simulations and analysis. Wherein the standard deviation of errors obtained is within [1.8 12.0 1.0] m, for a Gaussian generated code phase noise varying up-to 1.2m.