Three-dimensional fault-tolerant cooperative guidance law with constraints on relative impact velocity and attack angle

In the context of electronic countermeasures and precision strikes, this paper proposes a three-dimensional fault-tolerant cooperative (FTC) guidance law with constraints on relative impact velocity and attack angle to further improve the stability and strike capability of a missile swarm. The guidance law uses Fractional Power Extended State Observer (FPESO) to estimate the acceleration of the enemy target online, and introduces a nonlinear term into the traditional PIDSMC to derive the novel nonlinear PID sliding mode surface (NPIDSMC). Considering that communication in the cooperative process is prone to interference, different solutions are proposed for varying levels of interference. Simulation results show that, under ideal conditions and light interference, the proposed FTC-NPIDSMC-FPESO cooperative guidance law can achieve cooperative strikes with the desired impact velocity and attack angle. Under light interference, communication interference and node failures are handled through topology switching. In the case of severe communication interference, a fault-tolerant backup option is switched to fixed-time open-loop cooperative strikes to ensure the successful execution of the strike mission. Monte Carlo simulations further verify that the fault-tolerant cooperative guidance law exhibits strong adaptability and stability in electronic countermeasure environments.