Robust Trajectory Design Scheme under Uncertainties and Perturbations for Mars Entry Vehicle

For improving landing accuracy on future Mars missions, robust entry guidance schemes are required to improve landing accuracy. This paper analyzes the desensitized optimal trajectory design algorithm which augments the original fuel minimizing performance metric using a specific function of a sensitivity matrix to generate a trajectory. The trajectory is less sensitive to state uncertainties and perturbations. To enable the consideration of parameter uncertainties such as atmospheric density and aerodynamic characteristics, they can be treated as additional state and propagated using trivial dynamics in the trajectory design process. Simulation results indicate that the proposed trajectory design method considering all uncertainties and perturbations is able to generate a more robust trajectory.