Line of sight pointing and stabilization using fast steering mirrors

This study examines a technique that uses fast steering mirrors to perform line of sight stabilization for an infrared sensor system configured in the payload of a satellite. An optical-mechanical model is developed consisting of a dual-axis gimbaled pointing mirror two single-axis fast steering mirrors and a focal plane array infrared sensor. The interrelationships of the line of sight pointing vectors and the angular motion profiles for each of the optical mirrors are defined. From these relationships an algorithm is developed to provide position commands to each of the fast steering mirrors to perform the line of sight stabilization operation. The line of sight stabilization is done at a 25 Hz rate to provide a stable image to the focal plane array while the pointing mirror assembly remains in continuous motion. A dynamic model of the optical system and the servo control system for each of the fast steering mirrors is done using Matlab and Simulink. The results of the simulation indicate that the line of sight can be stabilized within an acceptable margin of image smearing for most applications.