低成本GPS时钟同步服务器设计

Design of Low-cost GPS Based Clock Synchronizer

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DP83848H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。

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 mierocontroller, 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 microeontroller, but also the method for resolving current date and time from the NMEA -0183 message. The Ethemet interface of the clock synchronizer is also designed using DP83848H PHYTER. At last, the Algorithm for synchronizing the clock of a client is presented in this paper.