Look angle tracking based three-dimensional impact time control guidance law with field-of-view constraint

This article proposes a three-dimensional impact time control guidance (ITCG) law without using time-to-go estimation, where the constrained field-of-view (FOV) is also considered. The guidance law design process is divided into two steps. First, the direction of the guidance command is selected to steer the look angle efficiently. Then, the desired look angle is constructed for controlling the impact time, and the guidance command magnitude is designed to track the desired look angle precisely in a prescribed time. By analyzing the look angle dynamics, the control gain is properly selected to guarantee satisfaction of the FOV constraint during the engagement. In addition, the feasible region of the desired impact time is derived. The effectiveness of the designed guidance law is validated by a series of numerical simulations.