Research On Algorithm Of Aircraft Trajectory Planning In Low-altitude Rescue

China is the country which suffered most serious natural disasters and various types of accidents around the world. Air rescue, as the significant part of three-dimensional rescue organic whole, has been remarkably concerned by all walks of society. Because it shows many advantages, such as faster, high efficiency, and less restricted. Apart from these advantages, as time goes by since Provisions for the use of low altitude airspace management has issue. The low-altitude safe operation of aircraft has become a hot research focus with the maturity of open policy on low-altitude flying. This paper is mainly about route planning of aviation aircraft in the low altitude emergency rescue. This research is divided into pre-tactical and tactical level on aircraft trajectory planning in low-altitude rescue. The ultimate purpose is to ensure that aircraft can independently search trajectories promptly and accurately.On the pre-tactical level, by combining the actual flight conditions, the optimal original trajectory is obtained. It is based on the single aircraft trajectory planning, three-dimensional mesh division of airspace and the improved A-star algorithm. Then with the outcome of single aircraft trajectory, combined with Time Window Theory, the thesis propose two methods about how to plan multi-aircraft trajectories without conflicts, and also to analyze the advantages and disadvantage by simulation experiments. On the tactical level, based on strategic trajectory and previous airspace grids, the paper puts forward SIBTP algorithm. This algorithm combines the advantages of both IMM algorithm and IIIA, and abandons the disadvantages when they are used separately, in this way, the new algorithm can ensure that the predicted trajectories are promptly and accurately. Based on the conflict resolution algorithm for trajectory prediction, with an effort to realize that aircrafts can avoid conflicts independently when there would be flight conflicts, the aircraft is treated as an independent intellectual agent and it is built on the airspace model according to visual flight collision avoidance rules. The optimal conflict-free trajectory has been worked out on the basis of priority rules and solutions to non-collaborate and collaborate trajectory adjustment. In the end, the thesis takes simulation tests on whether the SIBTP algorithm is actual in real time as well as be efficient.