The study of UAV 3-D track planning is less under the environment
with sudden threats and it mainly focused on determining static environment. In this article a two-stage planning method is proposed. The
planning process is divided into two stages: track pre-planning and track
amendment. ACO and ABC algorithms are adopted respectively. Track pre-planning can be determined beforehand in accordance with the informed hostile environment by ACO algorithm. And then, UAV flies according the on the pre-planning track. At the same time, it does real-time threats detection by airborne electronic equipments. When sudden threats
happen, UAV make track amendment by ABC algorithm after identifying
the location and type of threats. As just local amendment, the space is small and the data scale is less. In fact, ABC algorithm has the advantage of little time-consuming and quick search in small space with high-efficiency. And it can meet the requirement of accuracy and speed under sudden threats.Finally, two examples are tested and the simulation results show that the two-stage planning method is an effective track planning algorithm for the track planning problem under sudden environment.