Processing of Champ ACC and RSO Data in the Earth Gravity Field Determination

The high frequency accelerometer can provide non-gravitational perturbation force acceleration acting on CHAMP satellite. In CHAMP standard science product level-2 data, the acceleration, star camera, thruster firing and some corrections data are available. They play important roles in the determination of the earth gravity field. In this paper, the level-2 data (Day of year 1–100, 2002) are processed. Before applying the corrections, the curves of mean acceleration per day are very rough. After corrections, the curves show clear trend. On the other hand, the precise orbit of CHAMP is necessary for the determination of the earth gravity field. Now, the rapid science orbit data are provided by two organizations, GFZ and JPL. The data of a randomly chosen period (Day of year 267–269, 2002) from the two organizations are compared. The results of the comparison show that the difference between the two RSO data is notable, especially at the end part of orbit files. After getting rid of the end part of each file, there is no obvious system bias exists between the two RSO data and the magnitude of the difference keeps only about 0.1 m. Finally, some conclusions are drawn and some suggestions are given.