Design of imaging guidance system with double optical wedges

Abstract

Optical wedge is one kind of prism with small vertex angle and its characteristic of refraction can be used to deflect optical path. In this way, optical wedge can provide the light sources in different angular position. If rotating two optical wedges with certain angular velocity, the imaging point will be adjusted contiguously. Based on this, we propose an imaging guidance system that can utilize this feature to change the system optical axis and realize the target tracking or searching. In this system, servo motors are applied to drive optical wedges through the feedback loop. According to attitude information from carrier IMU (Inertial Measurement Unit), the optical system is located on one rotating frame which is controlled to isolate roll-channel disturbance from carrier. The decoupling in pitch and yaw channels can be done by cooperative rotation of the optical wedges. In this work, the image-forming principle of double wedges is analyzed and related control method is discussed.