Field-of-View and Impact Angle Constraint Guidance Law against Maneuvering Target with Nonlinear Observer

This paper focuses on dual-angle constraint of the impact angle and field of view (FOV) angle against maneuvering target. Firstly, the collision triangle theory is used to transform the guidance model constrained by the impact angle into a nonlinear second-order model about the satisfaction of final light-of-sight (LOS) angle by associating LOS angle with impact angle. Secondly, a guidance law with desired impact angle is proposed based on the state feedback method, and a nonlinear state observer is established to estimate the target acceleration term, which is unknown in engineering practice. Moreover, the design of the bias term instruction is completed in accordance with the switching logic method in order to realize the FOV constraints. It is worth mentioning that the selection of the middle point effectively alleviates the problem that the guidance command may jump violently during switching. Simulations presented to guarantee the effectiveness and robustness of proposed guidance strategy.