Research On The Routing Strategy Based On Space Debris Risk Perception In Satellite Optical Networks

In recent years,due to the advantages of wide coverage,large communication capacity and high strategic value,satellite network has become a strategic task related to national economic development and national security.However,with more and more space activities around the world,and collision events between space objects are emerging one after another,which will undoubtedly produce a large number of space debris.Due to the point-to-point transmission characteristics of laser,space debris will cause serious interruption risk to the normal transmission of intersatellite laser links.Therefore,it is of great scientific value and research significance to solve the problem of the decline of satellite optical networks communication quality caused by space debris.In order to solve the above problems,this paper focuses on the routing strategy based on space debris risk perception in satellite optical networks,and focuses on the three perspectives of "debris risk assessment,debris risk perception and debris risk avoidance".Aiming at the three core challenges of "universality,accuracy and efficiency" of the risk of inter-satellite laser link interruption caused by space debris,three technological innovations in satellite optical networks "risk assessment model of inter-satellite laser link interruption caused by space debris,inter-satellite laser link interruption risk perception method for space debris,and adaptive snapshot routing strategy based on space debris risk perception" have been completed.The scientific problem of "how to effectively reduce the risk of interruption of inter-satellite laser link communication caused by space debris" has been overcome,the research weakness in this field has been made up,and the robustness of satellite optical networks has been improved.Firstly,aiming at the problem of how to evaluate the risk of laser link interruption caused by space debris or debris cloud,according to the shape and behavior characteristics of space debris in different stages,the risk assessment models of laser link transmission interruption caused by space debris are proposed respectively.Based on the motion trajectories of different debris,the model can give the specific time range of laser link transmission interruption caused by space debris through the assessment model.It lays a foundation for designing debris risk prediction strategy more intelligently and accurately.Secondly,aiming at the problem of how to predict the risk of interruption of the inter-satellite laser link caused by space debris,a space debris risk perception method based on machine learning and space radar detection are constructed.In the spherical and annular stages of debris clouds,with the help of space radar detection system,the prediction method can give the link risk situation with time as the independent variable.In the omni-directional diffusion stage,based on two lines of data(TLE)from the North American Aerospace Defense Command(NORAD),the neural network is trained to explore the effect of different learning rates on the accuracy and training time.The simulation results show that when the learning rate is 0.02,the prediction accuracy of debris risk classification can reach 95%.Thirdly,aiming at the problem of how to reduce the impact of space debris on the performance of satellite optical networks,we propose an adaptive snapshot routing strategy based on flexible granularity(ASRSFG).When calculating the path,the algorithm takes the link risk caused by debris as an important factor,so as to effectively reduce the use of risky link.Aiming at the problem of debris may lead to the risk of unpredictable link interruption,we propose a space debris risk avoidable rerouting algorithm based on sub-adjacency topology(SDRARA-ST),which takes the risky link as the center,constructs the local topology based on the adjacent link and sub-adjacent link,and gives priority to finding the alternative path of the risk link in the sub-adjacent topology,so as to greatly reduce the topology scale of rerouting.The simulation results show that compared with the equal-length snapshot routing strategy(ESRS),the service success rate of ASRS-FG can be improved by about 5%,the link utilization can be improved by about 2%,and the average number of snapshot switching can be reduced by 54.88%.Compared with the rerouting algorithm based on global topology(RA-GT),the routing success rate of SDRARA-ST can be increased by about 10%,and the service transmission delay can be reduced by about 80%.