Abstract: A pinpoint autonomous navigation and control algorithm for lunar soft landing is presented in the paper. In the algorithm, first, the direction of landing spacecraft relative to the lunar center is determined according to the geometry relation of several ranging beams relative to the lunar surface. Second, attitude, velocity and altitude relative to the orbit reference frame are determined by combining the velocity vector provided by the velocimeter in the body reference frame. Third, the adaptive guidance and control method is selected based on the character of determined parameter. The algorithm can determine and control parameters of attitude, velocity and altitude based on direct measurement data and can improve the estimation and control accuracy of attitude, velocity and altitude, and can’t be affected by the inertial navigation error. Finally, the presented algorithms are validated by mathematical simulations.

Key words: lunar soft landing, autonomous navigation, guidance and control