Flat Stellar Dynamic Filter For Gyroless Attitude Estimation

In this paper, we present an innovative attitude estimation filter based on differential flatness of the satellite dynamics with Rodriguez Modified Parameters for star tracker only Attitude and Orbit Control System (AOCS) architectures. The main characteristic of this estimator is to be able to maintain the satellite Absolute Pointing Error (APE) within safe limits, avoiding safe hold mode recovery in case of long duration loss of measurements (attitude control with no measurements for 1000s). This filter has been selected for in flight testing on PARASOL CNES microsatellite, and will be experimented by May 2013.