We carried out a 26-day comparison of five simultaneously operated optical clocks and six atomic fountain clocks located at INRIM, LNE-SYRTE, NPL and PTB by using two satellite-based frequency comparison techniques: broadband Two-Way Satellite Time and Frequency Transfer (TWSTFT) and Global Positioning System Precise Point Positioning (GPS PPP). With an enhanced statistical analysis procedure taking into account correlations and gaps in the measurement data, combined overall uncertainties in the range of $1.8 \times 10^{-16}$ to $3.5 \times 10^{-16}$ for the optical clock comparisons were found. The comparison of the fountain clocks yields results with a maximum relative frequency difference of $6.9 \times 10^{-16}$, and combined overall uncertainties in the range of $4.8 \times 10^{-16}$ to $7.7 \times 10^{-16}$.

中文翻译：

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通过卫星技术直接比较欧洲主要和次要频率标准

我们使用两种基于卫星的频率比较技术：宽带双向卫星时间和频率传输，对位于 INRIM、LNE-SYRTE、NPL 和 PTB 的五个同时运行的光学时钟和六个原子喷泉时钟进行了为期 26 天的比较。 TWSTFT）和全球定位系统精确点定位（GPS PPP）。通过考虑到测量数据中的相关性和差距的增强型统计分析程序，光学时钟比较的总体不确定性在 $1.8 \times 10^{-16}$ 到 $3.5 \times 10^{-16}$ 范围内被发现。喷泉钟的比较产生了最大相对频率差异为 $6.9 \times 10^{-16}$ 的结果，以及在 $4.8 \times 10^{-16}$ 到 $7.7 \times 10^$ 范围内的综合不确定性{-16}$。