Comparison of powered descent guidance laws for planetary pin-point landing

Abstract

This paper conducts a comparison study of constrained powered descent guidance laws for planetary pin-point landing from the viewpoints of guidance performance and algorithm structure. All considered algorithms are reformulated to incorporate the critical elements of the powered descent problem, such as the free flight time, thrust limitation and terrain constraint. With these requirements to meet, the performance of guidance laws is evaluated and compared via simulations. Specifically, the nominal landing simulation verifies the guidance accuracy, fuel consumption, and real-time performance, as well as the hazard avoidance capability. Meanwhile, the robustness of guidance laws is evaluated by the Monte Carlo simulation, and the performance difference in final landing dispersion is interpreted by analyzing the algorithm structure and characteristics. Lastly, the discussion on practicability indicates the promise of optimization-based algorithms in future planetary landing missions.