Design And Implementation Of Space Network Protocol System Applied To CubeStar

With the continuous development of our country's space technology,the space mission is increasingly diversified,and the CubeSat with low cost,high functional density,short development period and flexible launch mode has become a new hot spot in the aerospace field.Different from the data centralized processing mode of the traditional satellite on-board computer,the CubeSat internally distributes its information processing to each subsystem module for distributed processing.Thus,the current satellite-integrated spatial network protocol cannot refer to its internal subsystem module.Aiming at this problem,this paper studies the CubeSat communication network and protocol based on packet routing and transmission control technology,and realizes the end-to-end communication between the CubeSat ground station and the intra-satellite subsystem,which has important application value.The main work of the thesis first analyzes the communication characteristics between the subsystems of the CubeSat,and analyzes the requirements of the communication protocol according to its characteristics.It proposes a spatial network communication protocol model that treats each subsystem as a node in the network.The overall design of the implementation includes the hierarchical division of the protocol,the selection of the protocol stack process model,the application process interface interaction flow design of the protocol stack,and the path planning of the protocol stack message.Then it studies some key technologies used in the implementation of high-performance network protocol stack,and proposes design implementation schemes based on these key technologies combined with the characteristics of CubeSat,including buffer management technology of protocol stack,zero-copy technology of protocol stack data,network interface of protocol stack management technology,routing technology and transmission control technology.Subsequently,the protocol stack system service request and processing are implemented for the common function of each CubeSat subsystem,including protocol management,network connectivity check,and node reboot service.Finally,the paper implements the prototype of the CubeSat space network protocol and builds a test system.It tests the protocol function of the design and the execution of each system service request in the protocol stack.The test results show that the system designed in this paper can meet the end-to-end communication requirements of the CubeSat subsystem,and proves the effectiveness of the algorithm and scheme designed in this paper.