UC Irvine

An atmospheric entry trajectory planner is developed that generates a feasible trajectory and associated bank angle profile. Feasibility denotes that the initial and final state conditions, the path and control constraints, and the nominal equations of motion are all satisfied. Feasible trajectories are easier to track, and thus enhanced performance is expected when the trajectory planner is combined with a tracking law for entry guidance. Insights from computing maximum crossrange trajectories are factored into the design of the planner, and as a result that it can generate trajectories to most of the landing footprint Drag profile design is central in the planning approach, but in addition both longitudinal and lateral motions are accounted for, including bank reversal planning, and the assumption of zero flight path angle is not required. Comparisons of trajectories created by the new planner and optimal trajectories and guidance simulation results using an algorithm based on the new planner demonstrate the performance improvements.