Comparison of Guidance Methods for Autonomous Planetary Lander

Abstract

Guidance methods for a powered descent planetary lander are examined. Several guidance laws are developed and analyzed including Apollo derived, modified Apollo, time efficient and fuel efficient methods. These laws are implemented using two different methods: Apollo approach, and real time. The equations of motion for an arbitrary planetary lander with sloshing fuel and a gimbaled nozzle are derived using a Newtonian approach. A six degree of freedom (6DOF) simulation of the vehicle system dynamics is programmed in Simulink to test the various guidance methods. The guidance methods are assessed using several different trajectories.