Landmark robust selection for asteroid landing visual navigation

Due to the limited onboard computational capacity, offline landmark sequence selection is widely considered to be beneficial to improve the observability, and thus estimation accuracy of asteroid landing visual navigation. Because of the inevitable pose uncertainty of spacecraft, conventional offline selected landmarks may be invalid and cause severe failure. To this end, the concept and calculation method of visual field intersection set (VFIS) are proposed considering the influence of pose uncertainty. By selecting the interior landmarks via VFIS, the effectiveness of offline landmark selection can be significantly improved. To further improve efficiency of the landmark sequence selection, repeated landmark observation based landmark selection index is proposed for performing further time series optimization on the observability-optimal landmark sequence. It is shown that the effectiveness of landmark selection is improved while ensuring high navigation accuracy. The feasibility and performance of the proposed method are verified through 4769 Castalia based numerical simulations.