Research on Composite Tracking Control Technology of Single Detector in Laser Communication

Abstract

The premise of space laser communication is the precise alignment of beacon beam, so the tracking technology of the composite axis is the key, and the coupling problem of coarse and fine composite tracking has become the research focus. Designed a tracking system based on single detector composite axis, and explained its principle and key technology. The method of coarse tracking and compensation to compensate fine tracking deflection amount is used to solve the coupling problem. The “open window” function of CCD(Charge Coupled Device) detector is adopted to solve the different requirements of the main axis and the sub-axis to the detector. The prediction of target trajectory during field of view switching improves the stability and greatly broadens the application scenarios of the system compared with the traditional method of single detector compound axis. An experimental system is built to verify the tracking performance and indicators. The experimental results show that the system’s coarse tracking error is controlled within 300$\mu$rad and the fine tracking error is controlled within 1 pixel under the disturbance of ±5°@0.1Hz. Combining the actual conditions, the overall tracking accuracy of the system is better than 3urad, which can realize accurate tracking of the beacon light and meet the application requirements of space laser communication.