Abstract:

The concept of a velocity-to-be-gained surface and a guidance law based on it for super-range exoatmospheric intercept is proposed for an interceptor with a fuel-exhaustion-shutoff solid rocket motor. Time-to-intercept determines the exclusive command thrust orientation in Lambert guidance, and the presented guidance process is composed of two stages: the optimal time-to-intercept is chosen to make the velocity-to-be-gained surface osculate the boost-time vs time-to-intercept plane during the zero-effort-intercept-achieving stage; then the velocity-to-be-gained surface slides on the boost-time vs time-to-intercept plane by decreasing the time-to-intercept durative to exhaust the redundant fuel. The concept of pseudo-zero-effort-intercept is used in the proposed guidance to avoid thrust orientation break at the shift of the two guidance processes. The J₂ item perturbation is considered in the guidance law, whose guidance precision is robust to motor parameter uncertainties. Simulation results demonstrate that the order of zero effort miss magnitude is kilometer and the guidance precision is robust to motor parameter uncertainties when using the proposed guidance law for super-range exoatmospheric intercept.

Key words: velocity-to-be-gained surface, zero-effort-intercept, Lambert guidance, J₂ item perturbation, robustness, perturbational equation