In this article, a 3-D nonlinear guidance law is developed for attacking a stationary target with desired impact angle and time. The guidance law is divided into two stages—impact angle control guidance (IACG) and proportional navigation guidance (PNG). In the IACG stage, a sliding-mode guidance law is established to guarantee the satisfaction of the impact angle constraint, and in the second stage, the 3-D PNG law is applied to ensure zero miss distance. The switch between the IACG and the PNG stages is determined by a guidance parameter related to the impact time constraint. By the virtue of Newton iteration method, an appropriate guidance parameter is obtained by solving an implicit nonlinear equality after a small number of iterations. Several numerical simulations are conducted to verify the feasibility and effectiveness of the proposed guidance law under different scenarios.

中文翻译：

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基于两阶段策略的三维冲击角度和时间控制制导律

在本文中，开发了一种 3-D 非线性制导律，用于以所需的冲击角度和时间攻击静止目标。制导规律分为两个阶段——撞击角控制制导（IACG）和比例导航制导（PNG）。在IACG阶段，建立滑模制导律以保证满足冲击角约束，在第二阶段应用3-D PNG法则以确保零失误距离。IACG 和 PNG 阶段之间的切换由与影响时间约束相关的指导参数确定。借助牛顿迭代法，经过少量迭代求解隐式非线性等式，得到合适的引导参数。