Time and Frequency Measurement
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Abstract
Time and frequency metrology rely on measuring and characterise atomic frequency standards as well as disseminate and compare distant atomic clocks to get precise and accurate time with the aim of providing synchronisations at less than the nanosecond level. Global Navigation Satellite System (GNSS) is applied to deliver time link between national metrology institutes maintaining their primary clocks by measuring time intervals of travelling signals from satellites to ground station receivers before determining characteristics and performances of atomic clocks as well as providing traceability to the Coordinated Universal Time (UTC). Their measurement results, performances and characteristics are presented in this paper.
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