Autonomous GNC technology for landing on small bodies

Due to long communication delay between target asteroid and base stations and complex mutable dynamic environment of small body, the traditional GNC mode based on deep space network (DSN) is no more suitable for landing spacecraft on small body. Probe must have the ability of autonomous GNC to perform landing safely. An autonomous GNC scheme for landing on small body polar region is presented in this paper. First, based on autonomous detection and tracking nature feature points, an autonomous optical navigation algorithm is built out; second, in order to achieve vertical landing, PD guidance control laws are designed to track desired descent trajectory and eliminate lateral position errors and velocity errors. Finally, the validity of the proposed scheme is confirmed by numerical simulation.