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采用传统A*算法进行大范围地图航迹搜索过程中,要收敛到最优解可能需要很长的时间和极大的内存需求,而且生产的航迹不能满足飞行器的约束条件。通过对A*算法进行时间复杂度的分析,找出算法中对计算时间影响最大的基本操作,提出了一种改进的A*搜索算法。该算法根据导航精度、数字地图误差等因素对搜索过程中网格的大小做出了确定,结合飞行器自身航迹约束条件和任务约束,在扩展子节点过程中大大缩小了搜索范围。仿真实验结果表明,该算法在大范围复杂地形情况下能规划出满足约束条件的最优航迹,并能大幅度降低搜索时间。
Traditional A * algorithm for large-scale map track search process, to converge to the optimal solution may take a long time and great memory requirements, and the production of the track can not meet the constraints of the aircraft. By analyzing the time complexity of A * algorithm, the basic operation which has the most influence on the calculation time is found, and an improved A * search algorithm is proposed. The algorithm determines the size of the grid in the search process according to the navigation accuracy and the error of the digital map, and greatly reduces the search range in the process of expanding the sub-nodes according to the track constraints and task constraints of the aircraft. The simulation results show that the proposed algorithm can find the optimal trajectory satisfying the constraints and reduce the search time significantly in a wide range of complex terrains.