Spline-RRT∗ based optimal path planning of terrain following flights for fixed-wing UAVs

This paper describes a path planning algorithm for fixed-wing UAV flights that follow the local terrain. The proposed algorithm utilizes a spline-RRT* planner in which the tree structure is extended using a spline method to generate smooth paths without any post-processing. In addition, a cost function ensures paths are sufficiently far from several hazardous positions and close to the surface of the local terrain. Therefore, the resulting paths are geometrically and dynamically feasible for terrain following flights, and are asymptotically optimal. A series of simulations demonstrates the successful utilization of the algorithm in a path planning application for terrain following flights for fixed-wing UAVs.