基于北斗卫星的纳秒级全球授时系统

Nanoseconds Deviation Timing Service System for Global Users Based on BDS

关键词:  授时  时间同步  北斗共视  全视  PPP  钟驾驭

Key words:  Timing service  Time synchronization  BDS Common-View  All-in-View  PPP  Clock steering

摘要:

北斗三号系统的基础服务可以为全球用户提供精度优于20ns的信号，更高精度的时间同步应用，需要如GNSS共视、全视、PPP或卫星双向时频传递等专用方法，成本高，并且需要专业维护，只适合小范围应用。在研究了各种高精度时间比对技术的基础上，基于国家授时中心的标准时间UTC（NTSC），提出了基于北斗卫星实时共视、实时全视和实时PPP多种技术互补融合的纳秒级全球授时方法。结合时延绝对标定与分段标定组合的设备时延标定，以及振荡器动态驯服等技术，建立了标准时间远程复现系统，由服务端和用户端两部分组成。服务端由国家授时中心维护，用户仅需要安装一台标准时间复现设备，并通过互联网或北斗短报文信道自动持续从服务端获取服务数据，即可在本地恢复出溯源至标准时间UTC（NTSC）的时间频率信号。系统可为全球用户提供与UTC（NTSC）偏差小于5ns的1PPS信号，以及万秒频率稳定度优于5×10-13、相对频偏小于5×10-14的10MHz信号，授时A类不确定度优于2ns。目前已经为多个行业提供服务。

Abstract:

The basic service of Beidou-3 system can provide global users with signals of accuracy better than 20ns. Higher precision time synchronization applications require special methods such as GNSS Common-View (CV), All-in-View (AV), Precise Point Positioning (PPP) or Two-Way Satellite Time and Frequency Transfer(TWSTFT). It is costly and requires professional maintenance. It is only suitable for a few users. Based on the study of various high-precision time transfer technologies and the National Time Service Center's UTC (NTSC), this paper proposes a nanosecond global time service method based on the integration of real-time Common-View, real-time All-in-View and real-time PPP.Combined with the equipment delay calibration technology of absolute delay calibration and piecewise calibration, and the oscillator dynamic steering technology, a time UTC(NTSC) remote replicating system is established. The system includes server and users. The server is maintained by the NTSC. The user only needs to install a standard time signal replicating device on the local, and automatically and continuously obtain service data from the server through the internet or BDS short message channel, so as to generate a local time that is continuously disciplined to UTC(NTSC). The system can provide users with 1PPS signal with deviation less than 5ns from UTC (NTSC) and 10MHz signal with 10000-second frequency stability better than 5×10-13 and relative frequency deviation less than 5×10-1４, and timing uncertainty with type A better than 2ns. At present, it has provided services for many industries.