中文摘要：

风场是影响无人机飞行速度的一个重要因素。为了缩短任务执行中的飞行时间，考虑战场环境存在外界威胁情况，提出了一种利用组合导航在线估计风场信息的无人机航迹规划方法。该方法基于飞行时间为代价，利用改进的A＊搜索算法对航迹进行顺风搜索，从而实现最短理想耗时的航迹规划。计算机仿真结果表明，与传统的最短航迹长度规划方法相比，无人机按该方法规划的航迹飞行时，理想耗时最少。

英文摘要：

To shorten the flight time of UAV, we propose an algorithm of UAV flight path planning on-line under battle field threats. Sections 1 through 3 of the full paper explain our method of flight path planning mentioned in the title, which we believe is better than the existing ones and whose core consists of： ＂UAV estimates the wind field information on-line using our proposed method during the flight. Then the choice of the extend nodes in A ＊ search algorithm is considered according to the wind direction and the cost function is designed as the flight time＂. Section 3 is entitled ＂Method of UAV Flight Path Planning On-Line in Wind Field Using Improved A ＊ Searching Algorithm＂ ; for convenience, we divide it into four sub-sections ： 3.1, 3.2, 3.3 and 3.4. Simulation results, presented in Figs. 4 and 5 and Table 2, and their analysis show preliminarily that the flight time is indeed less than that obtained with the traditional method based on the length of the flight path.