Spatial nonlinear guidance strategies for target interception at pre-specified orientation

Abstract

This paper addresses the problem of maximizing the warhead effectiveness, by achieving impact at the structurally vulnerable points of the targets. The impact direction is first defined using target frame, and then a unique relation between the desired impact angles and the desired line-of-sight angles is derived. Using this relation, two nonlinear guidance strategies, based on finite-time sliding mode and optimal control methods, are proposed to achieve interception of maneuvering targets at a pre-specified desired impact orientation. Unlike most of the existing three-dimensional guidance strategies, the proposed guidance strategies are derived without decoupling nonlinear coupled engagement kinematics into two mutually orthogonal planes and performing linearization, thereby avoiding possible performance deterioration for engagement with large heading errors. The performances of proposed guidance strategies are evaluated for various engagement geometries as well as constant speed and different realistic time-varying speed pursuer models subjected to aerodynamics parameter variations, and found to be satisfactory.