Abstract:
This paper presents a comprehensive investigation into the guidance strategy for the whole-process of lunar pinpoint landing. It introduces specialized guidance algorithms designed for each phase of the descent, with a focus on addressing real-time performance, fuel efficiency, and landing precision. In the braking phase, a multi-thrust powered explicit guidance (PEG) algorithm is implemented to optimize fuel efficiency while providing a flexible downrange capability. During the pitch-up phase, an adaptive terminal target adjustment based on PEG is employed. In the approach phase, a sequential convex optimization algorithm is developed to enhance landing precision and fuel efficiency. For the vertical descent phase, an open-loop guidance method is proposed to determine the optimal switching time based on the thrust profile of the optimal solution. Additionally, the impact of the approach phase inlet velocity on fuel consumption is evaluated using a receding horizon (RH) optimization framework, resulting in the formulation of an online guidance algorithm that achieves near-optimal fuel efficiency.