Modeling and design of fast steering mirror in image motion compensation for backscanning step and stare imaging systems

Abstract

To compensate for disturbances in an aircraft’s forward flight and variations in its attitude and angular velocity in the imaging process of photoelectric imaging system, a method of image motion compensation using a fast steering mirror was put forward. First, the working sequence of the image motion compensation system was designed. The position of the fast steering mirror is established by increasing the oblique wave to allow the fast steering mirror to move at the desired speed and compensate for the image motion speed. Then, a mathematical model of the fast steering mirror was established. A linear extended-state observer is designed to estimate the disturbance in real-time, and disturbance compensation is generated to offset the disturbance. Finally, a step response experiment and a tracking experiment were performed to test the characteristics. The step response curve shows that the system’s stable time is 1.8 ms. The tracking characteristic is determined by a given scan curve. The fast steering mirror can satisfy the requirement for a high-speed and highly precise tracking system. It improves the system’s interference rejection performance and reduces the difficulty of controller design.