In order to achieve more scientific returns for Mars, future Mars landers will be required to land at certain landing point with special scientific interest. Therefore, autonomous navigation is indispensable during the Mars approach, entry, and landing phase. However, the number of beacons or the Mars orbiters which can provide the navigation service is so limited and the line-of-sight visibility cannot be guaranteed during the landing period. So the navigation scheme especially the beacon configuration has to be optimized in order to efficiently use the limited navigation information. This chapter aims to analyze the feasibility and optimize the performance of the Mars Networks-based navigation scheme for the Mars pinpoint landing. The observability of navigation system is used as an index describing the navigation capability. Focusing on the relationship between the configuration of radio beacons and observability, the Fisher information matrix is introduced to analytically derive the degree of observability, which gives valuable conclusions for navigation system design. In order to improve the navigation performance, the navigation scheme is optimized by beacon configuration optimization, which gives the best locations of beacons (or the best orbit of navigation orbiters). This is the main approach to improve the navigation capability.
Part of the book: Space Flight