Modeling the Upper Atmospheric Density with the Help of Satellite Data

Abstract

In order to improve the prediction of the drag for low orbiting satellites, the DTM thermospheric model based on satellite drag data has been refined with two sets of data: the CACTUS accelerometer data obtained during the two years experiment in 1975–76 on board of the CASTOR satellite inclined at 30° on a 270/1270 km orbit, and the precise DORIS doppler tracking data from 1991 on the SPOT2 satellite orbiting near 830 km at a 90° inclination.

The CACTUS data which lead directly to the drag acceleration, hence to the atmospheric density as well as the DORIS data which cover about 50% of the SPOT2 orbit constitute a complementary asset for improving principally the He and O densities. Evaluation tests made in comparison with other models and in orbit restitution of drag sensitive satellites (SPOT2, ERS-1, STARLETTE) are presented.