Research On The Key Technology For Real-time Network Based On Reflective Memory Network

With the rapid expansion of computer network technology, the network performancedetermines the development of future navigation system. The traditional communicationmode features the limited real-time capbility. In order to further improve the real-time andreliability of navigation system transmisstion, a new network communication mode is neededto improve the real-time and reliability of navigation system network informationtransmission.Integrated navigation system(INS) plays an important role in ship navigationprocess,through the combination of each equipment on navigation system,the INS change thesingle navigation method,realize fast processing,transmisstion and display of navigationinformation,and provide real-time and reliable navigation information to the caption. TheIntegrated Navigation System is the background of this paper, in the part of system ofreal-time network the reflection memory network based communication mode is introduced.Both the constructed reflection memory real-time network and the existing ship navigationcommunication network make up the navigation system network platform. For the demand ofthe Integrated Navigation System, this paper’s the main work and the main research resultsare as follow:Firstly, through the analysis of the Integrated Navigation System network’scommunication, the reflection memory based real-time network is designed in two aspects:the real-time management and network protocol stack. In the real-time management aspect,the memory division, time management and interrupt management is researched. And in thenetwork protocol stack aspect, according to the navigation system requirements, a based onthe reflection memory network communication protocol stack is designed. A reflectionmemory network is constructed, and according to the principles and characteristics of thereflection memory network, a reflection memory network performance testing is performed.The software development platform VxWorks and crossing development environment arediscussed.Secondly, the hardware principle frame and the internal register key position setting ofVMIC-5565reflection memory card are studied. The reflection memory network interfacedriver which provide interface function for upper communication protocol and realize thesending and receiving data process, including equipment open shut, initialization, interfacecard configuration, data transmission and interrupt control. Finally, according to the characteristics and the functional requirements of the navigationsystem, the real-time management technology is designed in three aspects: memory division,time unification and interrupt management. And this paper also realizes the reflection memoryspace differentiate, timing of time synchronization and interrupt type and prioritymanagement. The TCP/IP communications protocol principle and algorithm is discussed andanalyzed. And a TCP/IP protocol stack, which has clear level, simple structure andlightweight, is implemented. The protocol stack is designed in four aspects: node datatransmission operation, memory management, application program interface and networkinterface. Five protocols are designed including the ARP protocol, IP protocol, the ICMPprotocol, the UDP and the TCP protocol in the transport layer, network layer and link layer.In the last part of this paper, each protocol stack module is tested. The test resultanalyzed in the aspects including real-time, reliability and scalability shows that the reflectionmemory based real-time network communication system proposed in this paper can meet therequirements of the navigation system.