The square root Unscented Kalman Filter in spacecrafts autonomous navigation

Concerning the problems in the process of the spacecraftpsilas autonomous navigation, the square-root unscented Kalman filter(SRUKF) is designed to estimate the relative state between the pursuing spacecraft and the target. C-W equation is discreted to iterate. For the case that all the measuring datas get from radars, the observing equation was deduced. Compared with the conventional extended Kalman filter(EKF), no Jacobian matrix is required to calculate in this algorithm, the computational cost is reduced and the estimation accuracy is also improved. Simulation results show that the algorithm can quickly converge even for large initial errors and is efficient.