On the Potential of a Combined Use of CHAMP Star Tracking and Accelerometry

CHAMP (Challenging Mini-Satellite Pay-load for Geophysical Research and Application) has opened a new era of global gravity field determination by satellites. Satellite platform, accelerometer, star tracker and actuators are modeled using a simulation tool in which orbit dynamics, satellite control systems, sensor and error characteristics are taken into account. The results of the simulations are compared with real CHAMP data obtained during the commissioning phase. From this comparison, insight is gained into the actual performance of these instruments as an integrated gravity sensing system. A possible cross-fertilization of star tracker and accelerometer data is discussed in some detail.