Small Satellite Magnetic Autonomous Orbit Determination Based on Modified UKF

Considering the design of small satellite request simply and low power, this article propose an approach to autonomous orbit determination based on measurements of 3-axis magnetometer. In order to elevate the efficiency of computing, in this paper a modified UKF (unscented Kalman filter) is used as the filter. It is based on the spherical simplex sigma-points selection strategy. Compare with symmetrical selection UKF in Unscented Transformation, this filter reduces the number of sigma points from 2n+1 to n+1 and retains model precision. In the filtering process, this strategy reduces the workload of computation effectively. The simulation results show that the magnetic orbit determination algorithm based on modified UKF is convergent and reliable.