An online estimation algorithm of landing footprints based on the drag acceleration-energy profile is proposed for an entry hypersonic vehicle. Firstly, based on the Evolved Acceleration Guidance Logic for Entry (EAGLE), drag acceleration-energy profiles are designed. To track the drag acceleration-energy profile obtained by the interpolation, a drag acceleration tracking law is designed. Secondly, based on the constraint model of the no-fly zone, flying around strategies are proposed for different conditions, and a reachable area algorithm is designed for no-fly zones. Additionally, by interpolating the minimum and maximum drag acceleration profiles, the terminal heading angle constraint is designed to realize the accurate calculation of the minimum and maximum downrange ranges by adjusting the sign of the bank angle. In this way, the distribution of landing footprints is more reasonable, and the boundary of a reachable area is more accurate. The simulation results under typical conditions indicate that the proposed method can calculate landing footprints for different situations rapidly and with the good adaptability.

中文翻译：

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满足禁飞区约束的快速生成入口着陆足迹的算法

提出了一种基于阻力加速能谱的在线足迹着陆估计算法。首先，基于改进的进入加速加速度指导逻辑（EAGLE），设计了阻力加速能量分布图。为了跟踪通过插值获得的阻力加速度-能量分布，设计了阻力加速度跟踪定律。其次，在禁飞区约束模型的基础上，提出了针对不同情况的绕飞策略，设计了禁飞区可达区域算法。另外，通过内插最小和最大阻力加速度曲线，设计了终端航向角约束，以通过调整倾斜角的符号来实现最小和最大下档范围的精确计算。通过这种方式，降落足迹的分布更合理，可到达区域的边界更准确。在典型条件下的仿真结果表明，所提方法能够快速计算出不同情况下的着陆足迹，并且具有良好的适应性。