M.+S.+Guilherme

Drag-Free Satellite (DFS) is a class of scientifc satellite missions basically for research on fundamental physics as well as geodesy. The Drag-Free Attitude Control System (DFACS) is the more complex technology on-board these satellites, with state of the art sensors and actuators specially developed for this purpose, and not yet tested in space. In the case of the accelerometer, to measure accelerations of the order of < 10−15 m/s2, or below, the inertial sensor is not yet tested in space. This key technology allows to reduce the residual accelerations on experiments on board the satellites significantly. In order to achieve this very low disturbance environment the Drag-Free Control system has to be optimized.
 * In-orbit calibration of drag-free satellites **
 * M. S. Guilherme, S. Theil, W. C. Leite Filho, H. Selig, H. Dittus, ZARM - University of Bremen **

The optimization process is required because of uncertainties in system parameters which demand a robustness of the control system. The paper will present an approach for the in-orbit estimation/identification of a drag-free control system.

The discussion includes the modeling, with scale factors and cross-talk couplings, possible excitation signals as well as simulation results. Keywords: Drag-free satellite; Calibration; Accelerometer; Parameter Estimation