The Research On Fast Acquisition Method In Space Optical Communication System

With the development of intelligent automobile technology and the support of the Ministry of Education on students' practice activities,the scale of various kinds of smart car competition for students has been gradually expanded.Space optical communication technology is a key technology of a new generation of satellite communication.It has great potential in global information and communication.Today,the amount of information is rapidly increasing,and society urgently needs large-capacity communication technology.How to provide users with large-capacity and reliable services in a limited time is one of the problems that space optical communication need to solve at present.However,space optical communication with large capacity and high reliability need to rely on precise alignment between the two communication terminals when establishing a communication link,which is very strict for the satellite optical communication system's acquisition,tracking,and pointing technology.When the two sides of the space optical communication are communicating,there may be background light interference of various stars,and the relative displacement between the two parties of communication is extremely great,and the communication environment is harsh.Therefore,research and optimization of fast scanning and acquisition technology in space optical communication system are urgently needed.In order to increase the scanning capture rate,increase the probability of capture on both sides,and optimize the performance of space optical communication systems.At present,how to apply the fast scanning acquisition technology to space optical communication systems has become one of the research hot spots at home and abroad.Based on the research of the composition and working principle of the Space Optical Communication ATP(Acquisition Tracking and Pointing)subsystem,this paper focuses on solving the problems of too long scanning and acquisition time and low acquisition probability during satellite communication.In the space optical communication system,the performance of the satellite acquisition,tracking,and pointing system is optimized,a fast satellite scanning scheme is proposed,and the satellite signal acquisition algorithm is studied to improve the scanning and acquisition performance of the space optical communication system.The main research work in the paper is as follows:(1)Analyze the scanning acquisition technology in space optical communication system.Based on the research of acquisition schemes and methods commonly used in space optical communication systems,a fast scanning scheme in space optical communication systems is proposed.This scheme analyzes various system parameters during the scanning process,and refers to the actual communication situation of space optical communication,establishes a two-beam hexagonal spiral scanning model,and simulates the model.The research results show that compared with the traditional hexagonal spiral scanning scheme,this scheme effectively shortens the scanning time and improves the probability of space optical communication terminal capture.(2)Based on the study of the variable-step scanning scheme,analyze the shortcomings of the variable-step scanning scheme,discuss the relationship between the capture probability and the scanning step,and propose a six-side combination of variable-step and equal-step-Shaped spiral scanning scheme.This solution is aimed at the actual communication situation of inter-satellite optical communi cation.Considering the large inter-satellite displacement during the communication process,the received signal has a large transmission delay and Doppler frequency shift.After analyzing the scanning step size and acquisition probability,a hexagonal spiral scanning model combining a variable step size and an equal step size was established,and the capture performance of the model was simulated.The research results show that this scheme shortens the scanning time compared with the equal-step spiral scanning scheme;compared with the variable-step spiral scanning scheme,the scanning step is optimized,the geometric missing scanning is overcome,and improved the performance of ATP subsystem scanning capture.(3)Investigate and discuss satellite signal acquisition and tracking algorithms in space optical communication systems.Focusing on the actual situation of satellite-ground optical communication links,considering the large optical energy transmission loss and the large background light interference during the communication process,based on the research of various satellite signal acquisition algorithms,a composite signal acquisition algorithm was proposed.This algorithm overcomes the shortcomings of long capture time of traditional serial capture algorithms and more suitable for satellite optical communication links.Compared with the traditional satellite signal acquisition algorithm,this algorithm improves the performance of the system's acquisition tracking.