Research On Key Technologies Of Inter-satellite Ad Hoc Network For Satellite Formation

At present,satellite network is widely used in military reconnaissance,navigation and positioning,environmental monitoring,navigation monitoring and other directions.With the increase of people’s demand for satellite functions,space networking and intelligent has become an inevitable trend,and the construction of space-based information network is urgent.Satellite network networking protocol is the basis and premise of satellite network can work normally.With the increasing of spacecraft node,its geometrical topology presents the characteristics of dynamic,complexity,heterogeneity.In order to adapt to the development of the satellite,we need to build a more flexible,reliable,large capacity,low latency of self-organizing networks.This paper mainly discusses several key technologies of satellite self-organizing network.1、Routing problem under the condition of complex heterogeneous dynamic network topology satellite node: The table-driven routing protocol in the ground mobile AD hoc network is improved to reduce the information exchange frequency and amount of information between satellites,so as to satisfy the characteristics of long transmission distance,limited resources and dynamic change of nodes in the space network,and shorten the routing establishment time of the satellite network to within 10 s.2、satellite network time synchronization problem: In order to improve the reliability of satellite network,this paper adopts the bidirectional time comparison method to offset the influence of air propagation delay,and extends the period of time synchronization through simple linear frequency correction.According to the possibility of multi-hop in satellite network,a cluster-based multi-hop step by step synchronization method is proposed,so that all nodes of the network can be synchronized with the network control center by self-synchronization method.3、Access control problem of each node channel in satellite network: Considering the dynamic characteristics of satellite network,this paper proposes two schemes: one is to introduce competition on the basis of fixed-slot channel access control;the other is to improve the channel access control on the basis of ground network to make it suitable for spatial information network.Keep sending and receiving data among nodes in order,reduce packet loss caused by collision,and make the end-to-end delay less than 500 milliseconds.Finally,the paper uses matlab software to verify the principle and simulation analysis of the improved ground network channel access control protocol,and uses ns3 to verify the improved routing protocol and the improved ground network channel access control protocol.The hardware platform demonstration and verification of the improved routing protocol,cluster hop-by-hop self-synchronization protocol and channel access control protocol are carried out in combination with specific engineering projects.