Local orbital frame predictor for LEO drag-free satellite

This paper is concerned with the on-board real-time position and rate prediction of the spacecraft centre-of-mass as input data to local orbital frame (LORF) determination for low-earth orbit drag-free satellites. Study and simulation results are justified by drag-free and attitude control of the GOCE satellite (gravity field and steady-state ocean circulation explorer), the LORF being the instantaneous reference for satellite attitude and scientific data. The paper focuses on modelling issues in view of disposing of an accurate orbit dynamics at lower frequencies, which is effective in reducing integration errors because of a narrow-band filter requested by the wide-band measurement errors. A further remedy in this sense is the addition of a second order disturbance dynamics leaving unexplained bounded noise components. Simulated results are presented with reference to the GOCE mission.