Stochastic Entry Guidance

In this paper, closed-loop entry guidance in a randomly perturbed atmosphere, using bank angle control, is posed as stochastic optimal control problem. The trajectory and the controls are both modeled random processes with statistics determined by dynamics, guidance, probabilistic structure of altitude-dependent atmospheric density variations. which parameterized sequence linear feedback gains, designed to steer probability distribution trajectories while satisfying bounds on allowable inputs maximum state errors. Numerical simulations Mars scenario demonstrate improved range targeting performance approximately 50% lower 1st 99th percentile final errors when developed scheme compared existing Apollo phase algorithm.