Research On Relative State Solution Of Distributed Spacecraft Based On Kalman Filter

Under the background of distributed spacecrafts, this thesis studies the measuring and calculating methods of relative state and focuses on relative state calculating arithmetic based on kalman filter, error model and calculating simulation method.On the basis of researching relative state measuring methods domestic and overseas, combined measuring method consisted of radio ranging, laser angling and sun sensitive organ orientation is presented to measure spacecrafts relative state. Error factors influencing measuring precision are analyzed and error model is built. Model of relative attitude is also studied. Measurement model of relative state is built.Through the research of traditional discrete kalman filter, measurement equation and state equation for kalman filter are built to calculate relative state. Dynamic model and geometric kinematical model are used to build state equation of relative position. Two methods calculating relative position and attitude simultaneously are advanced. One is to calculate relative position and attitude using modified adaptive kalman filter based on combined state equation. The other is to calculate relative position using modified adaptive kalman filter first, then calculate relative attitude using double vector.Distributed spacecrafts relative state calculating simulation system is designed. Relative state calculating is simulated using traditional kalman filter and modified adaptive kalman filter. The feasibility of modified adaptive kalman filter is validated.