Tracking and Positioning Maneuvering Target with Low Thrust Acceleration

The uncertainty of thrust acceleration will cause enormous error to model and track the accelerated motion of maneuvered target during orbit transfer process. An on-line minimum-variance estimator was developed for thrust acceleration applied to orbit transfer using discrete-time radar measurements. The mass-flow-rate of propellant was selected as a state variant, which was estimated by employing an integral state model and Extended Kalman filter. The variation equations for the measurement vector to mass-flow rate have been established to linearize the discrete-time measurement equations. The algorithm has applied successfully to maneuver process in commanding satellite into Geo-stationary orbit and lunar insertion orbit. The results show the algorithm developed here can monitor and determine whether engine works well or failure precisely and quickly during orbit transfer process.