Robust polynomial guidance law for power descending phase of lunar lander

This paper is on polynomial guidance law for future lunar lander in power descending phase. To achieve pin-point landing, the guidance trajectory needs to be accurate. Boundary conditions are required to solve the polynomial guidance law, but the guidance law is designed in bases where the boundary conditions are nominal. This paper proposes the method to obtain boundary conditions from approximation when initial error occurs and give optimal trajectory even with the initial error. This paper shows the series of different initial errors and discusses the effect of the approximate error to the trajectory and fuel consumption. The results give some ideas for future navigation technology for lunar landing, which has error at the start of their power descending phase.