AUTONOMOUS ORBIT CONTROL WITH POSITION AND VELOCITY FEEDBACK USING MODERN CONTROL THEORY

An apparatus and method for orbit control and maintenance techniques for both individual satellites and for multiple satellites in a constellation utilizing Modern Feedback Control for providing precise autonomous on-board navigation and control. This control system can place any satellite in any orbit position in a constellation, including the acquisition of the initial distribution for the constellation after satellite separation from launched vehicles. This system can also maintain distribution within a constellation, including station relocation and station keeping. Utilizing GPS position information, the orbit state vector is determined and modem advanced multivariable feedback control techniques, for example, linear quadratic Gaussian/loop transfer recovery controllers or optimal H-Infinity Robust Controllers are used to design a navigation and control system. The present invention uses a feedback control system designed to attenuate the external perturbations and provide robustness against unstructured uncertainty. The control problem is converted into first a tracking problem and a regulator design problem where the control problem is to minimize both position error and velocity error between the satellite (pursuer) and a nonexistent target satellite in an ideal orbit. The elimination of position error and velocity error result in an optimal orbital control system.