With the inclusion of satellite Internet as the information infrastructure in China's "new infrastructure" category,relevant domestic industries and scientific research institutes have successively carri...With the inclusion of satellite Internet as the information infrastructure in China's "new infrastructure" category,relevant domestic industries and scientific research institutes have successively carried out the design of broadband low earth orbit(LEO) constellation systems and key technical research.As the core technology for the satellite-to-ground network communications of a broadband LEO constellation system,routing technology is extremely important for the efficient and reliable transmission of various service data.Focusing on the two important broadband LEO constellation systems in China,in-depth analysis and simulation of the high dynamics of the satellite-to-ground satellites are conducted in this paper to obtain more accurate network topology changes and characteristics;then the adaptability of the ground standard IP routing protocol to the broadband LEO constellation system is analyzed,and an LEO constellation simulation scenario is built with the Opnet software.The simulation results of the convergence performance of the standard IP routing protocol are produced.The results show that the IP protocol does not perform well for LEO satellite constellation networks.Based on the studies,some solutions are proposed to take full advantages of the characteristics of LEO satellite systems.These can also provide a reference for the choice of intersatellite routing architecture and protocol technology for broadband LEO constellation in the future development.展开更多
The high speed of low earth orbit(LEO) satellites makes the terminals at each beam tend to switch rapidly and frequently.The predictable trajectories of LEO satellites allow for predictable terminal switching,therefor...The high speed of low earth orbit(LEO) satellites makes the terminals at each beam tend to switch rapidly and frequently.The predictable trajectories of LEO satellites allow for predictable terminal switching,therefore a simple and highly accurate orbit prediction model is required to swiftly obtain accurate switching time.This study utilizes the simplified general perturbations(Version 4)(SGP4) model to predict the LEO satellite trajectory of WT-1,an LEO satellite developed independently by the 54th Research Institute of China Electronics Technology Group Corporation(CETC).The obtained prediction results are compared with the actual telemetry data of the WT-1,which gives the accuracy of the SGP4 predicted satellite trajectory within 1 km.The terminal entry/exit beam timing is simulated by using the SGP4 model-predicted orbit and the satellite' s own telemetry data.The simulation result shows that the error between the SGP4 model-predicted terminal entry/exit beam timing and the actual timing is less than 1 s.The influence of terminal motion on prediction is discussed.The results show that the error caused by the movement of the ground terminal on the prediction is less than 0.687 s,and the SGP4 model has a definitely practical value for terminal switching determination in the LEO constellation.展开更多
文摘With the inclusion of satellite Internet as the information infrastructure in China's "new infrastructure" category,relevant domestic industries and scientific research institutes have successively carried out the design of broadband low earth orbit(LEO) constellation systems and key technical research.As the core technology for the satellite-to-ground network communications of a broadband LEO constellation system,routing technology is extremely important for the efficient and reliable transmission of various service data.Focusing on the two important broadband LEO constellation systems in China,in-depth analysis and simulation of the high dynamics of the satellite-to-ground satellites are conducted in this paper to obtain more accurate network topology changes and characteristics;then the adaptability of the ground standard IP routing protocol to the broadband LEO constellation system is analyzed,and an LEO constellation simulation scenario is built with the Opnet software.The simulation results of the convergence performance of the standard IP routing protocol are produced.The results show that the IP protocol does not perform well for LEO satellite constellation networks.Based on the studies,some solutions are proposed to take full advantages of the characteristics of LEO satellite systems.These can also provide a reference for the choice of intersatellite routing architecture and protocol technology for broadband LEO constellation in the future development.
文摘The high speed of low earth orbit(LEO) satellites makes the terminals at each beam tend to switch rapidly and frequently.The predictable trajectories of LEO satellites allow for predictable terminal switching,therefore a simple and highly accurate orbit prediction model is required to swiftly obtain accurate switching time.This study utilizes the simplified general perturbations(Version 4)(SGP4) model to predict the LEO satellite trajectory of WT-1,an LEO satellite developed independently by the 54th Research Institute of China Electronics Technology Group Corporation(CETC).The obtained prediction results are compared with the actual telemetry data of the WT-1,which gives the accuracy of the SGP4 predicted satellite trajectory within 1 km.The terminal entry/exit beam timing is simulated by using the SGP4 model-predicted orbit and the satellite' s own telemetry data.The simulation result shows that the error between the SGP4 model-predicted terminal entry/exit beam timing and the actual timing is less than 1 s.The influence of terminal motion on prediction is discussed.The results show that the error caused by the movement of the ground terminal on the prediction is less than 0.687 s,and the SGP4 model has a definitely practical value for terminal switching determination in the LEO constellation.
