The design of guidance law and error analysis in deceleration process of lunar soft landing

Guidance is critical for a probe to land on the moon surface successfully. This paper mostly discusses about the guidance law in deceleration process of lunar soft landing. Based on some hypothesis, it creates the dynamics model which is built in the coordinate system of soft landing. Then the suboptimal fuel-consuming guidance law is designed for the purpose of reducing fuel consumption. Output errors can represent an aggregation of sensor measurement errors, initial errors and stochastic disturbances. So it is necessary to execute error analysis on landing position accuracy in use of Maximum Deviation Method and Monte Carlo Method separately. The simulation results show that the guidance law can realize required accuracy.