The generation of new TA(NIM), which is steered by a NIM4 caesium fountain clock

Gao, Yuan; Gao, Xiaoxun; Zhang, Aimin; Wang, Weibo; Ning, Dayu; Wang, Chen; Li, Dawei; Liu, Xiaojin; Liu, Nianfeng; Wang, Ping; Li, Mingshou; Lin, Pingwei; Chen, Wei‐Liang; Lin, Yige; Li, Tianchu

doi:10.1088/0026-1394/45/6/s05

Cited by 12 publications

(7 citation statements)

References 1 publication

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“…As an important basic physical quantity, time plays an increasingly significant role in basic scientific research. It generally originates from a time scale mainly consisting of an atomic clock [1], [2], [3]. For instance, Coordinated Universal Time (UTC), which is produced by the International Bureau of Weights and Measures (BIPM), is derived from readings taken from about 450 free-running atomic clocks that are dispersed across the globe in more than 80 time laboratories [3], [4].…”

Section: Introductionmentioning

confidence: 99%

“…capability of the global navigation satellite system (GNSS) depend primarily on the accurate time provided by atomic clocks [7], [8], [9], [10], [11], [12]. Under these cases, the anomalous clock behaviors [13], [14], [15], such as frequency jumps and frequency drift jumps, would have a serious impact on the overall performance of the time scale [1], [16], [17].…”

Section: Introductionmentioning

confidence: 99%

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A Pseudo Random Pursuit Strategy for Atomic Clocks

Chen

Wang

et al. 2023

IEEE Access

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The atomic clock prediction algorithm is a critical part of the atomic time scale system to ensure its stability and accuracy. Random pursuit strategy (RPS) has been verified on the prediction capability of hydrogen maser and cesium clock in our previous works. This method is applied to deal with data impacted by different noise types including hetero-variance white noises and jumps. Nevertheless, it is difficult to apply RPS to real-time clock prediction, owing to its computational complexity. To alleviate it, we further improved our original algorithm by simplifying the random grouping using a pseudo-random strategy. In our work, theoretical analysis and necessary simulations of the pseudo-random pursuit strategy (PRPS) are presented, and the experimental results show PRPS's remarkable advantage in terms of operational efficiency. Compared to the original algorithm, it shows comparable accuracy and stability for prediction. PRPS takes only 1/p fitting time consumption as long as RPS starts from the second prediction. PRPS is faster, more efficient, and easier to employ when utilizing a clock predictor as the output of a system than RPS.INDEX TERMS Atomic clock, pseudo random, real-time prediction, anomalous behaviors, uncertainty, time complexity.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Pseudo Random Pursuit Strategy for Atomic Clocks

Chen

Wang

et al. 2023

IEEE Access

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“…Then BIPM announces, once a month through the FTP Server [2], information such as [UTC-UTC(lab)], weights of individual clocks contributing to TAI generation, frequency differences between individual clocks and TAI, frequency drifts of clocks participating in the computation of TAI, and so on. Some laboratories have developed PSFS such as cesium atomic fountain clocks and/or optical clocks and use them as a reference for generating their local time UTC(lab) or TA(lab) [3][4][5][6][7]. These PSFS are used to measure the difference in frequency with a clock (mainly hydrogen maser) participating in TAI generation.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of a real-time ensemble time scale corrected by the KRISS-PSFS using a reduced Kalman filter (Kred) algorithm

et al. 2023

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An ensemble time, which is indicated by TA (temps atomique, in French), was generated every minute by combining four active hydrogen masers with the reduced Kalman filter (Kred) algorithm. The TA frequency was averaged over 12 hours and then the mean frequency was steered to the Primary and Secondary Frequency Standards (PSFS) developed by KRISS with a micro-phase stepper (MPS). The steered and physically realized TA frequency is called KRISS Ensemble Time (KET). We investigated the frequency-state estimate outputted from the Kred algorithm and the control signal applied to the MPS, according to the abnormal temperature change of the room where the hydrogen masers were placed. When the frequency of the TA was corrected by the KRISS-F1, the Allan deviation (ADEV) of KET was 1.72×10-15 at the average time τ=1 d, and the variation of [UTC – KET] was stable within 2 ns for 75 days.

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“…The prediction of atomic clock behavior plays an important role in some applications, such as in the generation of time scales [1][2][3] and precise navigation provided by global navigation satellite systems (GNSSs) [4]. The performances of both systems strongly rely on atomic clock predictions.…”

Section: Introductionmentioning

confidence: 99%

Uncertainty analysis of clock prediction based on a random pursuit strategy

Wang

Zhang

Gao

et al. 2018

Meas. Sci. Technol.

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A random pursuit strategy was further developed to minimize the uncertainty of atomic clock prediction errors by applying a new weighting method in its predictor ensemble. It was applied to experimental data from a hydrogen maser maintained at the timekeeping laboratory of the National Institute of Metrology in China. Compared to the method in our previous work, the new strategy moderately reduces the prediction uncertainty of the hydrogen maser. It could be a useful tool for some cases of clock prediction or other aspects.

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The generation of new TA(NIM), which is steered by a NIM4 caesium fountain clock

Cited by 12 publications

References 1 publication

A Pseudo Random Pursuit Strategy for Atomic Clocks

A Pseudo Random Pursuit Strategy for Atomic Clocks

Characteristics of a real-time ensemble time scale corrected by the KRISS-PSFS using a reduced Kalman filter (Kred) algorithm

Uncertainty analysis of clock prediction based on a random pursuit strategy

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