基于有向无圈图的敏捷卫星姿态机动策略

针对敏捷卫星一次过境时间内的同轨拼幅观测和同轨多点连续观测模式的姿态机动策略问题，提出一种基于时间序有向无圈图的敏捷卫星姿态机动策略算法.该算法首先将区域目标和点目标转化为若干条带目标，然后通过将各个条带的观测时间窗口离散成一系列带有条带信息的时刻点，构造时间序有向无圈图，将敏捷卫星对地观测姿态机动策略问题转换为图论的寻找最优路径问题.仿真算例表明，该算法能够有效解决敏捷卫星同轨拼幅观测和多点连续观测的姿态机动策略问题，获得最大化观测覆盖收益同时机动时间消耗最小的姿态机动方案. 

Agile satellite attitude maneuver strategy study based on directed acyclic graph

Compared to the traditional Earth observation satellites, the agile satellites have more degrees of freedom for attitude maneuver and complex observation modes. An agile satellite attitude strategy based on time-ordered directed acyclic graph was proposed for the one-orbit strips-jointed and multi-spots observation modes for the agile satellites in its one pass time window. Firstly, the area target and the spot targets were divided into a certain number of strips. And then, the observation time windows of these strips were discretized into a series of time points with their strips information. With these time points, a time-ordered directed acyclic graph was constructed. After that, the attitude maneuver problem for the agile Earth observation satellites was described as the optimal path problem based on the time-ordered directed acyclic graph theory. The simulation examples prove the availability of the attitude maneuver strategy for the agile satellites in one-orbit strips-jointed and multi-spots observation modes based on time-ordered directed acyclic graph. And that the strategy, maximizing observation coverage and minimizing maneuver time cost would be got at the same time, was obtained by this method.