Control Method for High-Accuracy Fine Steering Mirror Based on Slow Sampling Rate of Tracking Sensor Signal

In the acquisition, tracking and pointing subsystem of free space laser communication system the tracking accuracy and the bandwidth of rejection frequency response are directly determined by the performances of the fine steering mirror of the compound axis tracking and pointing system. The slow sampling rate of the tracking sensor CCD signal currently limits the close loop bandwidth of the fine steering mirror. Based on the analysis of the slow sampling rate of the fine steering mirror, a multi-frequency sampling system of the fine steering mirror is designed, and the deviated mirror position signal is fused with the tracking sensor CCD signal, thus improving the close loop bandwidth of the mirror system and the rejection bandwidth. The simulation results have shown that the method can makes the bandwidth of the rejection frequency response enlarged, the close loop bandwidth frequency of the fine steering mirror approaches to the sampling frequency of the tracking sensor CCD signal, and the tracking accuracy is obviously improved in comparison to the original tracking sensor with slow sampling rate.