The mission of simultaneous attack and warhead lethality enhancement requires the constraints on impact time and angle in the guidance design. To this end, a two-stage guidance law considering constrained impact as well as the robustness against external disturbances and heading errors is proposed. The first stage is based on a circle involute geometrical rule that guarantees the desired velocity direction at the involute's end. With this goal achieved, the involute guidance is switched to the guidance of nullifying line-of-sight rate such that near-zero maneuver in the second stage is ensured. To achieve both impact time and angle constraints, a simple parameter determination approach is provided to find explicit solutions for the desired two-stage trajectory. Meanwhile, a robust two-stage guidance law is constructed to implement the geometrical rule, guarantee terminal constraints, and ensure robustness. The proposed technique is easy to implement, in that it does not involve model linearization, time-to-go estimation, and numerical optimization routine. Additionally, the achievable range of different constraints is analyzed considering practical issues such as initial launch angles, initial line-of-sight angles, and acceleration limits. Extensive simulations are carried out in various engagement scenarios under uncertainties and disturbances to validate the effectiveness and robustness of the proposed guidance law.

中文翻译：

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通过圆渐开线限制冲击的两阶段制导律

同时攻击和增加弹头杀伤力的任务要求在制导设计中限制撞击时间和角度。为此，提出了一种两阶段制导律，该法考虑了受约束的冲击以及对外部干扰和航向误差的鲁棒性。第一阶段基于圆渐开线几何规则，该规则在渐开线的末端保证所需的速度方向。通过实现该目标，将渐开线制导切换为使视线速率无效的制导，从而确保了第二阶段的接近零机动。为了达到冲击时间和角度约束，提供了一种简单的参数确定方法来为所需的两阶段轨迹找到明确的解决方案。同时，构建了鲁棒的两阶段制导律，以实现几何规则，保证终点约束并确保鲁棒性。所提出的技术易于实现，因为它不涉及模型线性化，走时估计和数值优化例程。此外，在考虑实际问题（例如初始发射角，初始视线角和加速度限制）的情况下，分析了不同约束的可达到范围。在不确定性和干扰下的各种参与场景中进行了广泛的仿真，以验证所提出的指导法的有效性和鲁棒性。和数值优化程序。此外，在考虑实际问题（例如初始发射角，初始视线角和加速度限制）的情况下，分析了不同约束的可达到范围。在不确定性和干扰下的各种参与场景中进行了广泛的仿真，以验证所提出的指导法的有效性和鲁棒性。和数值优化程序。此外，在考虑实际问题（例如初始发射角，初始视线角和加速度限制）的情况下，分析了不同约束的可达到范围。在不确定性和干扰下的各种参与场景中进行了广泛的仿真，以验证所提出的指导法的有效性和鲁棒性。