Method and apparatus for position and attitude control of a satellite

Abstract

An apparatus for regulating or controlling a satellite includes: at least one sensor for detecting reference targets such as stars, which is connected to arrangements for selecting and determining the position of reference targets, and to an arrangement for estimating model parameters of the satellite and of external interferences; a memory for storing a reference target catalog and a reference trajectory; a regulating unit for regulating the position of the satellite; and a filter that is connected to the arrangement for position determination of the reference targets, the arrangements for estimating the model parameters, the memory and the regulating unit. A method for regulating a satellite's position includes the following steps: detecting, determining the position of, and selecting reference targets; estimating model parameters of the satellite and external interferences; calculating the present position and/or attitude and motion conditions of the satellite on the basis of the estimated model parameters with the aid of dynamic models of the satellite motion; comparing the determined positions of selected reference targets with stored reference target data; and correcting the calculated position and/or attitude and motion conditions dependent on the result of the comparison. Such an apparatus and method achieve a high accuracy by successively updating and improving the accuracy of the reference target data.