Robust adaptive control of formationkeeping for a pair of satellites

Two robust adaptive control schemes (state-feedback and output-feedback) for formationkeeping of a pair of satellites are proposed. In contrast to most existing results, both control schemes are based on the nonlinear model directly, not on the simplified linearized model. In addition, the uncertainties and disturbances in the system such as the effects due to solar pressure, noncentral gravitational field, air drag, etc. are all considered. The objective of the control design is to force the relative position between two satellites to track a given reference signal while maintaining the desired Keplerian trajectory (in this case circular) for the master satellite. The results of this paper may be easily generalized to formationkeeping of a number of satellites.