低成本 GPS 时钟同步服务器设计

摘要

It designs an NTPv4 based low-cost GPS clock synchronizer .The clock synchronizer works in the client/server mode, and acts as a primary server in the network .Centering on LPC1768 microcontroller, the circuit of the clock synchronizer is designed .A HOLUX GR-87 GPS engine board is used as a reference clock in the clock synchronizer .The paper presents not only the electrical connection between the GPS engine board and LPC1768 microcontroller , but also the method for resolving current date and time from the NMEA -0183 message.The Ethernet interface of the clock synchronizer is also designed using DP 83848H PHYTER.At last, the Algorithm for synchronizing the clock of a client is presented in this paper .%设计了一种基于NTPv4协议的低成本GPS时钟同步服务器，该时钟同步服务器工作于客户/服务器模式，并在网络中作为主服务器使用。以LPC1768微处理器为核心，设计了时钟同步服务器的硬件电路。采用GR-87型GPS接收机作为GPS模块，文中不仅给出了GPS接收机与LPC1768微处理器的连接方式，还给出了从NMEA-0183消息中解析当前日期和时间的方法。采用DP83848 H芯片作为以太网物理层芯片，设计了时钟同步服务器的以太网接口电路。最后，还给出了实现时钟同步的算法。