Autonomous optical navigation and guide method for soft landing on small bodies

Considering the requirement of autonomous and real-time for small body landing, the problem of autonomous navigation and guidance for descent to a small body is discussed. Based on laser range finder and optical navigation camera to track the target landing point, an autonomous optical navigation algorithm is built out. By using the geometry relation of measure vectors and target point, normal direction of the landing plane and the target point position are obtained. In order to achieve vertical landing, the expecting descend trajectory characteristic is analyzed, and an impulse guidance and control law based on guide variable is presented. The small body landing control is decomposed into the tangential and normal direction control, by means of restricting the angle between line of sight of target point and normal direction of the landing plane. Finally, performance of the autonomous navigation and guidance system is verified by using the numerical simulation. The results show that the proposed methods can achieve high precision soft landing mission.