Two-Point Flight Path Planning Using A Fast Graph-Search Algorithm

Abstract

This paper presents a method, using a fast graph-search algorithm, of finding a feasible flight path for an air vehicle that flies between two locations. This flight path must satisfy the many constraints required to make the flight safe and efficient. We start by constructing a virtual terrain as a search space above the real terrain, to take into account real flight conditions and the limitations of the vehicle’s performance. Consideration of safe altitude, the horizontal safety distance of the flight path and the phase of take-off and landing are included. The idea of a virtual terrain could also eliminate a significant amount of search space, from 3-Dimensions to 2-Dimensions, which takes much less computation time, but which may have a shortcoming in rugged terrain where most path points are higher than the cruise altitude. Hence we propose a further process, which takes less than a second with no extra computational load, to overcome this problem. A dimensionless fuel consumption ratio between climbing and level-turn is proposed to deal with the case of levelflying between valleys. If climbing requires greater fuel consumption than taking a level turn, the algorithm chooses the level altitude flight path, hence improving the vertical smoothness of the flight. Using all these methods, including multi-resolution terrain and a fast searching method using a heuristic, we have successfully reduced the computation time of the algorithm to an acceptable level, and the simulation results show that our algorithm is feasible.