Research On GEO-to-Ground Laser Communication Tracking And Pointing System And Percision Transmission Technology

Satellite-to-ground laser communication has attracted wide attention because of its wide coverage area and small terminal volume.Laser communication satellite terminal uses GEO satellite as platform to establish communication link with the ground to realize data transmission between satellite and ground communication terminal.In order to build a stable and reliable satellite-to-ground laser communication link and realize satellite-to-ground laser communication,the GEO-to-ground laser communication tracking and pointing system is studied in this paper.Firstly,investigate the operating orbit environment of GEO satellites,and the working environment of satellite communication such as satellite vibration characteristics and vacuum environment is analyzed,so as to determine the design requirements of GEO satellite laser communication terminal.Through the analysis of the important parameters of the system,the technical indicators of the system are determined.Comparing the advantages and disadvantages of the existing laser communication tracking and pointing structure form,and combined with the system requirements,it is finally determined that the cross tracking support structure is selected for the tracking and pointing system studied in this paper.Secondly,most of the traditional tracking and pointing mechanisms adopt brushless DC torque motor drive mode,which requires the continuous operation of the motor,resulting in a large system power consumption.In order to solve this problem,a transmission mechanism with self-locking function is proposed.By applying the self-locking transmission mechanism to the tracking and pointing system of laser communication,the high precision axis pointing is completed,the optical axis is kept in the fine tracking field of view,the power consumption of the system is reduced and the service life of the system is improved.In this paper,the scheme design and principle analysis of precision transmission mechanism are carried out.According to the technical scheme,the mathematical model of the precision transmission mechanism is established,and the structural parameters of the transmission mechanism is determined by derivation and theoretical calculation.After the design of the transmission mechanism is completed,the mechanical analysis of the key components of the precision transmission mechanism is carried out to verify the transmission mechanism.Then,the mechanical structure of laser communication tracking and pointing system is designed with transmission mechanism.In the process of structure design of the tracking and aiming system,determine the materials and devices for each part of the tracking and pointing system,the shafting of the tracking and pointing system is designed in detail,the shafting precision is analyzed by calculating the shaft shake error,modal analysis method is used to simulate and verify the tracking and pointing system.The control system of tracking and pointing system is designed.Finally,this paper tests the tracking and pointing system and transmission mechanism according to the technical index of the system.The results show that both the tracking and aiming system and the transmission mechanism meet the technical requirements.It is verified that the design of this subject is reasonable,the mechanical structure is compact,and the key parameters meet the main technical specifications of laser communication.