Evasion and pursuit guidance law against defended target

This paper investigates a new approach for a scenario in which an Attacker attempts to intercept a defended aerial Target. The problem is formulated as a game among three players, an Attacker, a Defender, and a Target, with bounded controls. In the considered pursuit-evasion problem, the Target uses an optimal evasion strategy and the Defender uses an optimal pursuit strategy. The proposed approach focuses on the miss distance as the outcome of the conflict. The infeasible region for the initial Zero-Effort-Miss (ZEM) distance between the Attacker and the Defender, for a scenario in which the Attacker evades the Defender, is analyzed, assuming that the Attacker uses a control effort chosen from the permitted control region. The sufficient conditions are investigated under which, for ideal players, the Attacker can pursue the Target while evading the Defender launched by the Target. The guidance provided on how the Attacker can accomplish the task is divided into two parts. During the final time between the Attacker and the Defender, the Attacker chooses the control effort that guarantees the miss distance, and then uses the optimal pursuit strategy to accomplish the task. The derived guidance law is verified by nonlinear simulation. (C) 2017 Chinese Society of Aeronautics and Astronautics. Production and hosting by Elsevier Ltd.