Drag free control for the European satellite GOCE. Part II: digital control

Abstract

The paper gives an overview of the attitude and drag-free control (in short DFC) of the European Gravity Field and Ocean Circulation Explorer (GOCE) satellite. The DFC has been designed and tested in view of the Preliminary Design Review (PDR). The DFC is intended to enable the operations of a gravity gradiometer for the Earth gravity field recovery. The DFC has been fully designed on a simplified discrete-time model derived from the 'fine' dynamics of the spacecraft and its environment, as outlined in a companion paper. The DFC has been tested against severe uncertainties and its code has been integrated into GOCE end-to-end simulator.