This paper addresses the pursuit-evasion problem involving three agents -- a purser, an evader, and a defender. We develop cooperative guidance laws for the evader-defender team that guarantee that the defender intercepts the pursuer before it reaches the vicinity of the evader. Unlike heuristic methods, optimal control, differential game formulation, and recently proposed time-constrained guidance techniques, we propose a geometric solution to safeguard the evader from the pursuer's incoming threat. The proposed strategy is computationally efficient and expected to be scalable as the number of agents increases. Another alluring feature of the proposed strategy is that the evader-defender team does not require the knowledge of the pursuer's strategy and that the pursuer's interception is guaranteed from arbitrary initial engagement geometries. We further show that the necessary error variables for the evader-defender team vanish within a time that can be exactly prescribed prior to the three-body engagement. Finally, we demonstrate the efficacy of the proposed cooperative defense strategy via simulation in diverse engagement scenarios.

翻译：本文研究了涉及三个智能体——追逐者、逃逸者和防御者的追逐-逃逸问题。我们为逃逸者-防御者团队开发了合作制导律，确保防御者在追逐者接近逃逸者之前将其拦截。与启发式方法、最优控制、微分博弈公式以及近期提出的时间约束制导技术不同，我们提出了一种几何解，以保护逃逸者免受追逐者的来袭威胁。所提策略计算高效，且预期随着智能体数量增加具有可扩展性。该策略的另一个吸引人之处在于，逃逸者-防御者团队无需知晓追逐者的策略，并且能够从任意初始交战几何构型下保证拦截追逐者。我们进一步证明，逃逸者-防御者团队的必要误差变量可在三体交战前精确预定的时间内消失。最后，我们通过在不同交战场景中的仿真验证了所提合作防御策略的有效性。