Research On Topology And Routing Of Laser/Microwave Inter-satellite Link Cooperative Network For Navigation Constellation

The inter-satellite link is an important part of the modern global navigation satellite system.The wide coverage of the global satellite navigation system and the convenient communication and networking capabilities of the Concurrent Spatial Time Division inter-satellite link system make the Beidou satellite navigation system inter-satellite link network more abundantly functional and data transmission pressure.In this context,it is necessary to build a more powerful satellite network.High-speed,high-accuracy laser inter-satellite links are ideal for building navigation constellation satellites with more powerful network communication capabilities.However,at this stage,the laser inter-satellite link cannot completely replace the microwave inter-satellite link,and the laser inter-satellite link and the microwave inter-satellite link need to be cooperatively networked.The laser inter-satellite link has distinct characteristics compared to the microwave inter-satellite link.In this paper,the collaborative network consisting of two links of laser inter-satellite link and microwave simultaneous time-division inter-satellite link cooperative network is taken as the research object,and the network topology and routing method of its networking are studied.The research work mainly includes the following aspects:1.The networking characteristics of the inter-satellite link system in the microwave concurrent time-division and the performance of the network transmission are analyzed.The advantages and networking characteristics of the laser inter-satellite link are analyzed.On this basis,an architecture for efficient transmission of collaborative networks is designed,and the basic constellation that satisfies the global coverage and better coverage of multiple coverage in China and surrounding areas is calculated.2.Aiming at the transmission characteristics of the cooperative network laser link transmission and the microwave link access,the topology design method of the laser network and the time slot arrangement method of the microwave inter-satellite link are proposed respectively.In the design of the laser network topology,improve its transmission performance as a backbone network.The network transmission delay under traffic load is optimized.The simulated annealing algorithm is used to optimize the network connection relationship of the laser intersatellite links.The algorithm can well solve the network topology design problem under the network composed of laser inter-satellite links of different scales.In the design of the microwave inter-satellite link time slot arrangement method,the ability to access the laser network is improved.Aiming at the problem that when the number of laser inter-satellite link satellites is insufficient,the time slot resources of the microwave inter-satellite link satellite access backbone network is limited.Based on the best matching Kuhn-Munkres algorithm,the time slot arrangement method is designed.The algorithm also has a good inter-satellite measurement performance while making full use of the backbone network to access the time slot resources.3.Aiming at the characteristics of cooperative network time-varying link and non-time-varying link cooperative networking,the communication delay of collaborative network is modeled.Based on the Dijkstra shortest path routing algorithm in time-invariant networks,the shortest path routing algorithm under the cooperative network of the Big Dipper is designed.4.Finally,the collaborative network simulation scenario is built based on OPNET simulation software,and the design content of this paper is verified.The results show that the performance of the inter-satellite link network of the Beidou satellite navigation system is significantly improved after the addition of the laser intersatellite link,and the cooperative network has better transmission performance.