Cooperative robust line‐of‐sight guidance law based on high‐gain observers for active defense

Abstract

SummaryIn this paper, a three‐body confrontation problem of a target‐defender team against an attacker is studied in three dimensions. To eliminate the system deviation that arises from the linearization of the model, a second‐order nonlinear model with normal acceleration as its input is established to describe the relative motion of three vehicles in three‐dimensional space. A high‐gain observer is designed to estimate the line‐of‐sight angular velocity in the case that system states cannot be measured. Based on disturbance rejection technique, a robust line‐of‐sight guidance law is developed in virtue of the estimated information for the target‐defender team so that the defender is able to intercept the attacker. Key features of the developed guidance law lie in that it does not need to know guidance information of the guidance law of the attacker in advance, and is robust to disturbance and uncertainty. Simulation examples are provided to demonstrate the effectiveness of the proposed guidance law.