Development of terminal guidance law and PWPF modulator for near space interceptor based on finite time theory

Based on the finite time theory, the finite time convergence terminal guidance law and Pulse Width Pulse Frequency (PWPF) modulator are proposed for intercepting near space high-speed maneuvering targets. First, the mathematical model and working principle of terminal guidance with PWPF modulator are introduced. Second, the finite time convergent guidance law is designed. The convergence conditions and properties are proved based on the finite time theory, and areextended to the condition considering the thrust constraint. Finally, considering the fast convergence of Line of Sight (LOS) angular rate and the minimum working time of the engine, the parameters of the PWPF modulator are designed. The simulation results show that the LOS angular rate converges to zero in finite time before the end of terminal guidance. The guidance law, robust to the maneuvering target, has higher guidance precision. and can avoid frequent on-off of the engine to save fuel.