UTC(NIS) Steering Techniques with Few Number of Atomic Clocks

Abstract

Till now, the Coordinated Universal Time of the National Institute of Standards (UTC(NIS)), which is the Egyptian Time Scale (TS), is generated by using a single Cesium (Cs) atomic clock. But, the reliability and frequency stability of UTC(NIS) in that case are limited by those of the single Cs clock. In the near future, UTC(NIS) will be generated by using the average atomic TS (TA(NIS)) from an ensemble of Cs clocks to enhance its reliability and frequency stability. In this paper, a simulation is carried out to check the effectiveness of generating TA(NIS) from the 3 Cs clocks of NIS clock ensemble. Results from TA(NIS) simulation will be presented and discussed before it is used for UTC(NIS) generation in the real-time. Also, in this paper, the two steering techniques that are currently used for UTC(NIS) generation instead of TA(NIS) to enhance its time accuracy with respect to the international TS (UTC) are introduced. Results show that these techniques were effective and able to reduce the TS difference values (UTC-UTC(NIS)) to below ± 100 ns in the last 3 years, as recommended by the international Consultative Committee of Time and Frequency (CCTF).