Design And FPGA Implementation Of Time Synchronization System Based On IEEE802.1A

With the rapid development of aerospace technology and the emergence of new application scenarios,the requirements for end-to-end latency in spacecraft communication networks is increasing.Traditional Ethernet cannot meet the strict requirements of spacecraft communication networks in terms of latency during data transmission due to its time delay uncertainty.With the emergence of time-sensitive network technology,its deterministic service based on a time synchronization mechanism has become a research hotspot for real-time application areas such as aerospace.In this paper,based on the IEEE802.1AS time synchronization protocol in time-sensitive networks,a time synchronization system is designed and implemented to meet the low latency requirements of spacecraft communication networks.The main research contents of this paper are concluded as follows:(1)In this paper,we deeply study the IEEE802.1AS time synchronization protocol and design a time synchronization system based on FPGA hardware implementation.The design uses ZUC102 board to realize the sending and receiving of g PTP messages and the algorithm in IEEE802.1AS protocol by means of hardware logic design,and constructs the communication link of the system through the network communication board of FMC interface to complete the overall design of the time synchronization system.(2)Aiming at the link delay asymmetry and crystal stability problems in the time synchronization system,a time deviation model is constructed in this paper to describe their effects on the time synchronization deviation.Based on this model,the Kalman filtering algorithm is used to realize the tracking and correction of time deviation,and combined with the sliding average filtering method to suppress the time deviation jitter,so as to improve the time synchronization accuracy.(3)Finally,the system is simulated and tested and verified at the board level.The simulation tests verify the correctness of the design of each sub-module in the time synchronization system.The board-level experiments show that the time deviation correction algorithm can improve the system time synchronization accuracy.The time synchronization system designed in this paper achieves the time synchronization accuracy within 300 nanoseconds between two nodes in the g PTP domain and meets the design requirements.