Real-time path planning for low altitude flight based on A* algorithm and TF/TA algorithm

Most of Path Planning Algorithms are applied independently when solving real-time path planning problems. However, utilizing multiple algorithms simultaneously can avoid the disadvantages of their each as much as possible. This paper divides the real-time path planning mission into two grades employing different algorithms. A* algorithm is used to plan a path avoiding threats which is divided into several great circle cruise parts and penetration cruise parts. A kind of Terrain Following/Terrain Avoidance (TF/TA) algorithms is used to create the penetration cruise track based on the path planned by A* algorithm according to the terrain and threats. The search nodes of A* algorithm are merely created on demand and the terrain following algorithm only detects a finite length of track in front of the aircraft during the flight, so the computational resource and time consumed can be reduced. The path planning method can run online to generate an economical and safe path to avoid the threats by low altitude flight.