ORBIT DETERMINATION USING GPS CONSIDERING DIRECT SOLAR RADIATION PRESSURE MODEL FOR THE TOPEX/POSEIDON SATELLITE

Abstract. The main target here is to determine the orbit of an artificial satellite, using signals of the GPS constellation and least squares algorithms through sequential Givens rotations as the method of estimation, with the aim of improving the performance of the orbit estimation process and, at the same time, minimizing the computational procedure cost. Perturbations up to high order geopotential and direct solar radiation pressure were taken into account. It was also considered the position of the GPS antenna on the satellite body that, lately, consists of the influence of the satellite attitude motion in the orbit determination process. An application has been done, using real data from the Topex/Poseidon satellite, whose ephemeris are available at Internet. The best accuracy obtained in position was smaller than 5 meters for short period (2 hours) and smaller than 28 meters for long period (24 hours) orbit determination. In both cases, the perturbations mentioned before were taken into consideration and the analysis occurred without selective availability on the signals measurements