Research On Fine Tracking And Fast Steering Mirror Technology In Space Laser Communication

Space laser communication has the advantages of high communication rate,large communication capacity,high anti-interference and anti-interception ability,and low power consumption.In order to ensure the long-distance transmission of the optical transceiver,the communication beam divergence angle of the space laser communication is very small,which requires both parties to maintain a very high dynamic alignment accuracy,so high tracking accuracy and high reliability of acquisition,pointing and tracking(APT)system.The fine tracking system further suppresses the coarse tracking residual.The final accuracy of the APT is determined by the fine tracking unit.The fast steering mirror system is used as the servo execution unit of the fine tracking to adjust the direction of the internal optical path in real time,and correct the off-target amount of the light spot.The beam at the end is aligned precisely.Therefore,the control design of the fine tracking fast mirror system is of great significance for the research of the fine tracking technology of space laser communication and the improvement of the system tracking effect.Based on the composition and working principle of the fine tracking fast steering mirror system,this paper systematically studies the key technologies of the fine tracking system in space laser communication by means of principle analysis,modeling and simulation,and experimental testing.A model reference adaptive control strategy based on nonlinear gain is proposed for the fast steering mirror system,and a fine tracking sliding mode controller is designed by adopting the sliding mode variable structure control idea for the fine tracking system.The numerical simulation of the designed controller is carried out using MATLAB,and the effectiveness of the designed controller is verified.Finally,an experimental platform is built,and the related technologies in the research content are applied to the fine tracking fast mirror system.The experimental results show that the fast steering mirror has good dynamic performance under the designed control scheme,and the fine tracking system has a good tracking effect.The practical application of space optical communication system lays the foundation.