Design And Implementation Of An Automatic Retransmission System For Proximity-1 Protocol

With the development of deep space exploration technology,multi spacecraft missions have become the mainstream.As a result,CCSDS proposed a new system i.e.Proximity-1 space link protocol,based on the existing COS protocol and AOS protocol.Due to the influence of the terrain and the relative motion of the spacecraft,the received signal will be seriously distorted in deep space exploration mission.The researches on Proximity-1 protocol have great practical significance and far-reaching influence on the development of China's Mars exploration,the "Beidou satellite" network communication and other space projects.By learning from the general communication system,automatic retransmission system has been designed and implemented based on the CCSDS Proximity-1 protocol and the characteristics of Proximity-1 space link.Firstly,the overall scheme of the system is given,and then the architecture of the whole system,the design of the hardware scheme are provided.Secondly,after a comprehensive comparison of the advantages and disadvantages of stop and wait,go-back-N and selective ARQ,Proximity-1 with GBN-ARQ schemes is designed according to the ARQ interface in it.Besides,the frame length and the length of the window in the design are analyzed and optimized.Thirdly,by using OpenGL and LabWindows/CVI development platform,the mission is implemented on up layer interactive software for system control and 3D communication representation,and on protocol transceiver software for protocol and ARQ process simulation,respectively.A variety of data file interface and software control mode are also provided.Finally,the whole Proximity-1 space link automatic retransmission system is simulated.The test environment is setup with the hardware and software platform.Complete tests and analysis on the intermediate frequency and radio frequency signals of the transmitter,the TCP/IP connection of the software,the protocol simulation and the ARQ retransmission performance are provided.The testing results show that the design of the system is complete and correct.