The Research Of Clock Synchronization For Comprehensive Dispatching System

The high-speed railway comprehensive dispatching system integrated the train operation dispatching, the transportation planning management, the power dispatching, the motor train unit dispatching, the comprehensive maintain system, the passenger service and so on. It is very strict for the synchronization of clocks for the comprehensive dispatching system. The paper focuses mainly on research of clock synchronization in the comprehensive dispatching system.Firstly, the paper introduces the traditional ways of clock synchronization and it points out the lack of traditional synchronization ways. Secondly, the paper expounds the ways of clock synchronization in the distributed systems. According to the network topology of the high-speed railway comprehensive dispatching system, the paper put forward the clock synchronization network based on staged-distributed type, and use the operation mode is client/server mode. For ensuring reliability of clock synchronization in large complex network of the high-speed railway comprehensive dispatching system, the paper use the redundant server of NTP. Fatherly, the paper analysis all kinds of the primary algorithm.. According to the clock synchronization network based on staged-distributed type in the comprehensive dispatching system and using the operation mode is redundant server of NTP, the paper implements the data filter algorithm, Intersection algorithm and Combining algorithm, and implement the modified of the client Time Offset in using the methoed of combining the Linear Phase Adjustment with the Nonlinear Phase Adjustment. Then, The paper designs the data structures of the clock synchronization program, and designs NTP client and server program for the comprehensive dispatching system based on the NTP algorithm and the adjustment strategy of the time offset in this paper. Additionally, the paper designs two operation modes for the client software, one mode operates under single-server and another operates under multi-server, the two modes can switch each other automatically and it is due to the fault states of network. Finally, the paper makes the clock synchronization experiments in the multilayer and multilevel structure of education network and LAN to compare with the traditional clock synchronization.