基于Motorola VP Oncore接收机的新型GPS共视时间传递系统

本文设计了基于Motorola VP Oncom接收机的新型GPS共视时间传递系统，用高分辨时间间隔计数器测量本地原子钟和GPS接收机输出秒信号的时差，通过读取导航电文得到GPST和指定卫星的时差，于是得到本地原子钟与指定星钟的时差，实现GPS共视法单站测量。为确保系统严格共视，使用多线程和同步监测机制设计了可靠的同步控制策略，两套系统的超短基线单通道共视比对结果表明，系统性能稳定，比对精度(用原始共视数据的均方根表示)不大于4．9m，该系统可应用于SDH通信网时间同步、交换机时间同步等高精度定时领域。

New GPS Common-view Time Transfer System Based on Motorola VP Oncore Receiver

A new design of GPS common-view time transfer system is presented. The time difference between the 1pps of local clock and that of Motorola VP Oncore GPS receiver may be obtained by using high-resolution time interval counter, and the time difference between GPST and certain satellite clock may be obtained by reading navigation message from GPS receiver. As a result, the time difference between local clock and certain satellite clock may be calculated, and the one-site measurement of GPS common-view may be implemented. For ensuring the strict common-view, a synchronized control strategy using multi-thread mechanism and an auto-detecting block is designed. The raw data of actual short-baseline single-channel common-view measurement shows that the Root-Mean-Square is better than 4.9ns. The system may be widely used in time synchronization in Synchronous Digital Hierarchy (SDH) communication network and exchange and other timing application cases.