Two-stage guidance law with impact time and angle constraints

A novel two-stage missile guidance law for impact time and angle control is proposed. This guidance law is derived based on the nonlinear engagement dynamics without using small angle assumption. In order to control both impact time and impact angle, a two-stage scheme is developed. This scheme is composed of a nonsingular sliding mode guidance law for the first stage and a switching target strategy for the second stage. The guidance law is switched from the first stage to the second stage when the switching condition is attained, which can ensure that the guidance law is switched at the right time to satisfy impact time constraint. The switching target strategy in the second stage can achieve impact angle control with high accuracy. Impact time and angle can be controlled simultaneously under this two-stage scheme. Numerical simulations are performed to demonstrate the performance of the proposed method.