Guidance system having a body fixed seeker with an adjustable look angle

Abstract

A missile guidance system with a fixed body missile seeker having an adjustable look angle. The missile seeker has a fixed camera whose look angle is adjustable to keep a moving target within the field of view of the camera. The target is tracked by a tracker to generate target angle and line of sight rate signals. The target angle signal is input to pointing angle adjustment apparatus which adjusts the look angle of the camera. The pointing angle adjustment apparatus may comprise a stepper motor that controls the angular position of a gimbal on which the camera is mounted. Alternatively, the pointing angle adjustment apparatus may comprise one or more stepper motors that control an adjustable zoom lens or a plurality of optical wedges, respectively. A body angular rate output signal of a body-fixed inertial measurement system is summed with the line of sight rate signals from the tracker to determine the inertial line of sight rate of the moving target. The inertial line of sight rate is driven to zero or a low fixed value by a control system to accurately track a target. The control system and missile dynamics generate a body angle signal that is input to a difference circuit along with a camera pointing angle signal output by the pointing angle adjustment apparatus. The difference circuit generates a desired camera pointing angle that is input to the pointing angle adjustment apparatus to point the camera at the target.