Post-processing ROA data clocks for optimal stability in the ensemble timescale
Post-processing ROA data clocks for optimal stability in the ensemble timescale
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DOI：
10.1088/0026-1394/40/3/301
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发表时间：
2003-06
期刊：
影响因子：
2.4
通讯作者：
F. Galindo;J. Palacio
中科院分区：
文献类型：
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作者：
F. Galindo;J. Palacio
近年来，在时间和频率实验室中检测到的时钟之间的某种相关性是开发经典“三角帽”方法的修订版的主要原因，该方法是估计一组时钟的频率不稳定性的数学工具。该方法已制定牢记时钟之间的依赖性的可能性，并已推广到一个合奏的N时钟[1-5]。它基本上由最小化的目标函数，互相关系数的二次和，建立的约束条件的（估计）绝对协方差矩阵的正定性的时钟。后来，在[6]中提出了在相关时钟的情况下计算最佳权重的矩阵公式。这种加权程序的合奏时间的不稳定性的影响进行了评估，模拟时钟的基础上，当相关性被适当地考虑到，并在这种情况下，当它被忽略。该文件建立，作为一个主要结论，数学处理将用于通常情况下的弱相关性。在本文中，我们提出了一个总结所涉及的理论，然后应用程序的最佳加权时钟使用真实的数据时钟在真实的天文台德拉阿尔马达（圣费尔南多，西班牙）。最后，我们讨论了所获得的结果。
In recent years, a certain correlation detected between clocks at time and frequency laboratories has been the main reason behind the development of a revised version of the classical `Three-Cornered Hat' method as a mathematical tool to estimate the frequency instability of a set of clocks. The method has been formulated keeping in mind the possibility of dependence among clocks and has been generalized to an ensemble of N clocks [1–5]. It basically consists of the minimization of an objective function, the quadratic sum of cross-correlation coefficients, with the constraint condition established by the positive definiteness of the (estimated) absolute covariance matrix related to the clocks. Later on, a matrix formulation to calculate the optimal weights in the case of correlated clocks was presented in [6]. The impact of this weighting procedure on the instability of the ensemble time was evaluated, on the basis of simulated clocks, when correlation was appropriately taken into account and in the case when it was neglected. That paper established, as a main conclusion, the mathematical treatment to be used in the usual case of weak dependence. In this paper, we present a summary of the theory involved, and then apply the procedures to optimal weighting of clocks using real data clocks at Real Observatorio de la Armada (San Fernando, Spain). Finally, we discuss the results obtained.