关键词: 小天体, SPC特征, 特征选取原则, 飞行器定位, PDOP

Abstract: In the SPC navigation process of asteroid detection, navigation feature selection mainly depends on subjective judgment and causes massive fault tests. In this work, by analyzing the processes of shape model reconstruction, image rendering, template matching and spacecraft localization, we propose four principles of feature selection applying to natural feature tracking during aircraft descent phase, including manufacturability, specificity, light adaptability, and distribution uniformity, etc. The threshold conditions corresponding to the principles are analyzed quantitatively. We validate our principles using real imagery from NASA’s OSIRIS Rex mission to asteroid Bennu, along with the accuracy of local elevations, the correlation performance and the navigation comparison data from NASA NAIF SPICE kernels. The results show that the successful matching rate of rendered features against onboard imagery can reach 96.85%.

Key words: asteroid, SPC feature, feature select principle, spacecraft localization, PDOP