A fast-steering mirror based image stabilization system for Star Sensor

During the operation of the airborne star sensor, star image is caused to be blurred by the atmosphere disturbance or carrier vibration, which influences measurement precision and decreases
observation efficiency. The Fast-steering Mirror based image stabilization system in star sensor is presented to compensate the image motion to keep the optical path stable. First of all, the centroid of the star target is calculated by the barycenter method in a certain window, which is determined by searching from the star image acquired by star sensor in an improved centroid calculating method. Consequently, the miss distance between star target and image center could be obtained. According to this, the controlling system drives the voice coil motor to ensure the fast-steering mirror moving to compensate the carrier motion, which keeps the star staying at the center of the image and enhances the image stability. The experimental results show that, when the correcting frequency of the system is about 100 Hz and the exposure time is 8 ms, the vibration amplitude reduced by about 3 pixels. The influence of carrier vibration is mostly eliminated, and the impact of atmospheric disturbance has also been improved. Thus the observation efficiency is obviously increased.

Conclusion

In conclusion, the application of fast-steering mirror based on micro-mechanical image stabilization system in star sensor is introduced and analyzed in this paper. The experiment results demonstrate the stabilization system could mostly eliminate the effect of carrier vibration, and the impact of atmospheric disturbance has also been improved. It could reduce the centroid hysteresis and also improve the ability of the sensor to keep up with fast-moving stars. This image stabilization system is suitable to airborne star sensor with great dynamic and has great potential in high resolution measurement system with atmospheric disturbance or carrier vibration.