Impact angle guidance law to prevent the detection degradation of a seeker

Abstract

An impact angle control guidance (IACG) law applicable to a homing missile equipped with a strapdown imaging seeker is investigated against a stationary target. Given an impact angle constraint, usually a detour is generated and the change of the look angle is inevitable. A rapid change of the look angle can cause a fast relative target motion in the seeker’s image plane, which can lead to a motion blur effect. The main contribution of the paper is that an IACG law is designed to minimize the look angle rate to prevent the loss of the target signal. Based on the variational approach, the optimal look angle rate that satisfies the impact angle constraint is derived, and the guidance law is designed to follow the optimal look angle rate. Using various weighting functions, a guidance law that has low sensitivity to the initial condition is also developed. Numerical simulation supports the performance of the guidance law. The result illustrates that the proposed guidance law reduces the rate of look angle in comparison with other IACG laws.