Link calibration against receiver calibration: an assessment of GPS time transfer uncertainties
Link calibration against receiver calibration: an assessment of GPS time transfer uncertainties
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DOI：
10.1088/0026-1394/51/5/476
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发表时间：
2014-10-01
期刊：
影响因子：
2.4
通讯作者：
Uhrich, P.
中科院分区：
文献类型：
--
作者：
Rovera, G. D.;Torre, J-M;Uhrich, P.
在使用全球定位系统(GPS)发送的信号时，我们直接比较了两种不同的技术，用于相对校准远程时间尺度之间的时间传递。相对校准估计设备的延迟或相对于参考设备的时间传输链路的延迟。它是基于一些移动的GPS设备在网络中的站点之间的循环，并以此为基准来测量本地设备。可以考虑两种技术：第一，通过计算本地GPS设备的硬件延迟来进行站点校准；第二，计算两个远程时间尺度的参考点之间的时间传递的全局硬件延迟偏移量。相对于另一种技术，最后一种技术称为“链路”校准，即“接收器”校准。这两种技术需要不同的现场测量，这改变了不确定性预算，我们讨论了这一点和相关问题。我们报告了2013年秋季在法国巴黎的巴黎天文台(OP)、法国卡伦的蔚蓝海岸天文台(OCA)和英国赫斯特蒙丘的NERC空间大地测量设施(SGF)之间组织的一次校准活动。旅行设备包括两个不同类型的GPS接收器，以及所需的信号发生器和分配放大器，以及一个时间间隔计数器。我们给出了不同的不确定度预算计算方法，当比较相对链路校准和相对接收器校准时，硬件延迟不确定度的改善因子为1.2到1.5。
We present a direct comparison between two different techniques for the relative calibration of time transfer between remote time scales when using the signals transmitted by the Global Positioning System (GPS). Relative calibration estimates the delay of equipment or the delay of a time transfer link with respect to reference equipment. It is based on the circulation of some travelling GPS equipment between the stations in the network, against which the local equipment is measured. Two techniques can be considered: first a station calibration by the computation of the hardware delays of the local GPS equipment; second the computation of a global hardware delay offset for the time transfer between the reference points of two remote time scales. This last technique is called a 'link' calibration, with respect to the other one, which is a 'receiver' calibration. The two techniques require different measurements on site, which change the uncertainty budgets, and we discuss this and related issues. We report on one calibration campaign organized during Autumn 2013 between Observatoire de Paris (OP), Paris, France, Observatoire de la Cote d'Azur (OCA), Calern, France, and NERC Space Geodesy Facility (SGF), Herstmonceux, United Kingdom. The travelling equipment comprised two GPS receivers of different types, along with the required signal generator and distribution amplifier, and one time interval counter. We show the different ways to compute uncertainty budgets, leading to improvement factors of 1.2 to 1.5 on the hardware delay uncertainties when comparing the relative link calibration to the relative receiver calibration.