Research on Satellite Autonomous Orbit Determination Method Based on the Unscented Particle Filter with Embedded Earth Sensor Correction

Abstract

The direct earth horizon and starlight observation with earth sensor and star sensor is often used in the satellite autonomous orbit determination, which is a stable autonomous navigation method but with some defects that need to be improved. On the one hand, both the orbit state equation and measure equation are nonlinear, in which only the 2nd zonal harmonic of the non-spherical earth gravity is introduced while the other perturbation terms are regarded as white noise, which in fact all these terms have certain models themselves that are usually non-Gaussian distribution. In this case, Unscented Particle Filter (UPF) is present to be used for the satellite autonomous orbit determination; On the other hand, the error of earth sensor is a vital problem for the precision of satellite-earth center distance determination, which will damage the observation of orbit information. In this paper, the UPF uses the Unscented Kalman Filter (UKF) to generate sophisticated proposal distributions. It can not only avoid the limitation of the UKF which only apply to Gaussian distributions but also avoid the limitation of the standard PF which can not include the new measurements. The other improvement to the autonomous orbit determination method is embedding a earth correction based on star sensor measurement into the UPF observation step, which enhances the final orbit determination precision a lot. The simulation results show that the presented method has higher accuracy and more stable characteristic than the standard PF and UKF, especially when the earth correction is absent.