Research On Key Technologies In Intersatellite Optical Communication

In order to meet the increasing demand for information capacity and transmission rate,satellite laser communication technology has emerged as a new generation of space communication technology.It has a wide range of applications and potential market,which will be a hotspot in the world.It is very difficult to establish a communication link between satellites efficiently and quickly.In order to overcome this problem,the inter-satellite laser communication system has a large spatial environment,a long communication distance,narrow laser beam and low transmission power.Key technologies are studied in-depth.In this paper,the components of the inter-satellite laser communication system are designed,and the working principle and processing of system are briefly presented.The functional analysis of the ATP(Acquisition,Tracking and Pointing)system is carried out according to background of the subject,and then the components and working principle of the ATP subsystem are designed.According to the designed scheme,the principle and processing of establishing the communication link between two satellite laser communication terminals are analyzed,the link establishment time is deduced and decomposed.Based on the inter-satellite laser link equation,the link power is budgeted and the influence of the parameters on the link efficiency and the link margin is analyzed.In order to maintain the stability of the laser communication link,the paper analyzes the link interruption and establishes the model,and determines the relationship between link probability and tracking accuracy.In this paper,the capture technology is studied deeply,strategy and important parameters of the system are analyzed,and the numerical simulation is carried out.Compared with different capture programs and methods,the paper selects the most suitable capture program and methods.The standard deviation of the initial offset angle and the field of uncertainty(FOU)are studied in depth,and the theoretical model is established and numerical analysis is carried out.The model of probability is deduced,the composition and influencing factors are analyzed,while numerical simulation analysis is carried out.In-depth discussion of the scanning step,the paper achieve different scanning step of high efficiency scanning;to prevent leakage caused by jitter,the paper introduces additional overlap factor.The fast scan mode 1 and the fast scan mode 2 are analyzed,and the corresponding scanning interval model is established.The multi-field scanning theory model is proposed based on the single-field scanning theory.In this paper,the spiral scanning technique is studied in detail,the scanning acquisition scheme is optimized to further reduce the link establishment time.Based on the statistical principle,the models of scanning and acquisition are deduced,including spiral scanning,rectangle spiral scanning,diamond spiral scanning and hexagonal spiral scanning.The model takes into account all the conditions of system parameters,different scanning field theory,and different scanning modes.The influence of important system parameters on the capture performance of various models is analyzed,including the FOU,scanning step,communication distance,bandwidth of beam,beam angle and detector response time.By changing system-related parameters,the model is applicable to a system both with a beacon and without a beacon.Scanning mode and path are combined with each other,and the scanning performance of corresponding model is compared with the numerical simulation.In order to verify the correctness of model,the experimental scheme of the verification scan acquisition model is designed and a large number of experiments are carried out.The statistical results show that the scanning performance of the hexagonal spiral scanning is the best.At the same time,analysis and comparison of the advantages and disadvantages of different structural turntable are analyzed.The paper selects altazimuth structure and designs the construction.In this paper,a parabolic low-pass filter algorithm is proposed according to the actual demand,and the detected signal is denoised.The principle and working processing of parabolic low-pass filter algorithm are analyzed,and the expression of frequency window function is deduced.According to the minimum mean square error criterion,the expression of optimal frequency and cut-off frequency is deduced.The parabolic low-pass filtering algorithm and other filtering algorithms are simulated and experimented.The experimental results and the simulation results show that the parabolic low-pass filtering algorithm can quickly process the original signal,effectively preserving the local details of the information while improving the signal noise ratio.