Research On Time Synchronization Optimization Of Train Communication Network Based On PTP Protocol

With the rapid development of high-speed train network communication technology,train equipment has increasingly high requirements for time accuracy,making the introduction of time synchronization technology in time sensitive networks into onboard networks a future development trend.The core of time synchronization technology is to achieve time consistency between various subsystems of the train through synchronization.The traditional NTP protocol’s millisecond synchronization accuracy cannot meet the requirements of train communication.In contrast,the PTP protocol can support sub microsecond synchronization accuracy and is currently widely used in various industrial fields.However,there is still relatively little research on train time synchronization technology.Therefore,it is of great significance to study the time synchronization problem of train network communication and further achieve high-precision time synchronization of train equipment.The specific research content of this article is as follows:(1)A thorough analysis was conducted on the train communication topology structure in the IEC61375-1 standard and the time synchronization mechanism in the PTP protocol.Based on this,a universal train communication network topology and a fully synchronous train communication network topology suitable for synchronous structures were designed.(2)Based on the clock domain theory of PTP protocol,clock domain architectures for universal train communication network and fully synchronous train communication network were designed.A complete PTP protocol time synchronization architecture was designed using the OMNeT++simulation platform.Normal clock,boundary clock,and transparent clock were implemented through parameter configuration,and simulation models of the two train communication networks were built based on these clocks to achieve the train time synchronization process.The correctness of the model was verified through simulation analysis.(3)An improved clock servo system framework was proposed and designed to address the synchronization optimization problem.In the framework of improving the clock servo system,a time synchronization optimization algorithm was proposed,and Kalman filter optimization algorithm,multi model PI control optimization algorithm,and time compensation algorithm based on multi model PI control optimization algorithm were designed and implemented.(4)Verify the synchronization optimization algorithm using the OMNeT++simulation platform.Taking the universal train communication network and the fully synchronous train communication network as the research objects,the synchronization offset of Kalman filter optimization algorithm before and after,traditional PI control algorithm and multi model PI control optimization algorithm,as well as traditional clock servo system and improved clock servo system were compared.The experimental results show that the proposed synchronization optimization algorithm significantly improves the synchronization accuracy and stability in the network.