Characterizing the performance of GPS disciplined oscillators with respect to UTC(NIT)
Characterizing the performance of GPS disciplined oscillators with respect to UTC(NIT)
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表征 GPS 规范振荡器相对于 UTC(NIT) 的性能
DOI：
10.1109/freq.2005.1574017
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
V. Zhang
中科院分区：
文献类型：
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作者：
M. Lombardi;A. Novick;V. Zhang
全球定位系统振荡器（GPSDO）现在是许多实验室和校准设施的主要时间和频率标准。它们通常被接受为自校准标准，其用户通常认为它们符合制造商的规格。为了更好地了解GPSDO的实际性能，本文提出了一种方法，其特征的长期和短期的性能，使用UTC（NIST）的时间尺度作为参考。然后，它描述了如何使用这种方法来表征四个GPSDO，包括两个使用恒温石英振荡器（OCXO）作为其时基，两个配备了铷振荡器。在两个60 d的测量间隔内，使用相同的天线同时测试所有四种器械。在第一个60 d测量期间，使用先前测量的天线位置，并将相同的坐标应用于所有四个设备。在第二个60 d测量期间，每个GPSDO对天线的位置进行独立的测量，并应用自己的坐标。在两个60 d的时间间隔内测量每个GPSDO的定时输出（每秒1个脉冲）和频率输出（10 MHz）。使用低噪声双混频器时差系统来表征每个器件的10 MHz输出的短期频率稳定度，并给出和总结了所有测量结果。
Global Positioning System Disciplined Oscillators (GPSDOs) are now the primary standard of time and frequency at many laboratories and calibration facilities. They are typically accepted as self-calibrating standards, and their users generally assume that they meet the manufacturer's specifications. To gain a better understanding of the actual performance of GPSDOs, this paper presents a method of characterizing both their long and short-term performance that uses the UTC(NIST) time scale as a reference. It then describes how this method is used to characterize four GPSDOs, including two that use an oven controlled quartz oscillator (OCXO) as their time base, and two equipped with a rubidium oscillator. All four devices were simultaneously tested using the same antenna over two 60 d measurement intervals. During the first 60 d measurement, a previously surveyed antenna position was used and the same coordinates were applied to all four devices. During the second 60 d measurement, each GPSDO performed an independent survey of the antenna's position and applied its own coordinates. Both the timing output (1 pulse per second) and the frequency output (10 MHz) of each GPSDO was measured during both 60 d intervals. A low-noise dual mixer time difference system was used to characterize the short-term frequency stability of each device's 10 MHz output, and all measurement results are presented and summarized.