Research On The Key Technology Of ATP System For Space Optical Communication

Space optical communication is a new technique which has advantages such as high transfer rate, low consumption and strong anti-interference abilit.Many countries attach import attention to the research of space optical communication. But it leads to many technology problems in the beam pointing because of the narrow laser beam. So the research on acquisition, tracking and pointing (ATP) technology becomes especially important.Firstly, this paper introduces the concept of space optical communication and it's advantages compared to microwave communication,and discusses the key techniques of space optical communication,the significance of ATP in space optical communication is explained in detail, besides, as an emphasis,the configuration,work principle and key technical indicators of ATP are studied.Secondly, ATP system's tracking performance is analyzed, the error signals which impact tracking performance are discussed in detail,which include the coupling effect between the gimbals and the acceleration interference because of the gimbal's imbalance,the characteristics and sorts of noises in the Q-APD signal detecting subsystem ,the vibration of tracking platform and vibration rejection methods are also analyzed.The impact of error signals to tracking precision is discussed with emphasis. According to the characteristics of the error signals, this paper sets up mathematical models and presents feasible methods to eliminate the errors.In the aspect of hardware circuit design about ATP system, the emphasis are the function and the working process of A/D, D/A conversion circuit and photo- electricity encoder signal feedback circuit. At the same time, the corresponding circuit structure charts are given.The capability and structure of the main components of circuits are illuminated.Finally, ATP implementation scenario adopts composite axis servo system structure,at the base of above research, some correction methods to enhance ATP system's precision are given,concretely,one method is to enhance the precision of rough coarse part by a series compensation controller,the other design is the direct method of digital control to enhance the precision of fine part. Besides,these methods have been simulated with Matlab by computer, the results show the methods are feasible.