Field-of-View Constrained Guidance Law for a Maneuvering Target With Impact Angle Control

Most existing impact angle control guidance (IACG) laws that consider the reduced seeker field-of-view (FOV) focus only on a stationary or a nonmaneuvering moving target. In actual warfare, however, a number of targets are capable of maneuvering with lateral acceleration, which prohibits the existing FOV-constrained IACG laws from guaranteeing the reliable performance. In this article, we develop a guidance law that ensures the accurate IACG with obeying the FOV constraint against a maneuvering target. The proposed guidance law is based on the engagement kinematics against a maneuvering target and structured as a sliding mode controller to cope with unknown disturbance such as the normal acceleration of the target. The introduced sliding surface structure includes a sigmoid function of which output is limited in magnitude in order to restrict the missile look angle within the preset limits. In consequence, the proposed law has the capability to fulfill IACG without violating the FOV constraint against a maneuvering moving target. Numerical simulations that support the effectiveness of the proposed guidance law are also included in this article.