Abstract: | Coincident with the installation of a new measurement system, the National Bureau of Standards has also developed a new philosophy for the generation of both UTC(NBS) and atomic time, TA(NBS). Several benefits have resulted from this new direction. First, a more uniform UTC(NBS) scale was achieved in order to meet the increased requirements of our users. Second, improved synchronization of UTC(NBS) with UTC ( Universal Time Coordinated) has been achieved. The frequency stability of UTC(NBS) is typically about 1 x 10 for averaging times of one day and longer and synchronism is now maintained to within about 1 microsecond of UTC indefinitely. Previously five microseconds was a realistic goal. Third, a new Kalman type algorithm with more robust performance is used to generate TA(NBS) totally independent of the generation of UTC(NBS). TA(NBS) is still steered in rate toward the frequency given by the NBS primary Frequency standards. Fourth, a significantly improved working time and frequency reference is readily available. This reference supports the research and development of new frequency standards, and also supports our calibration services. This improved time and frequency reference is constructed by computing UTC(NBS) in final form every two hours. A real-time output signal is then steered in frequency to keep its time within a few nanoseconds of the officially computed value. And fifth, a very stable frequency reference is obtained by using all of the clocks available in the NBS clock ensemble. This time scale -- denoted AT1 -- is used tor all of the NBS frequency stability calibrations, and is also used to generate UTC(NBS). This new approach has been tested for more than a year and the resulting improvements have now been documented. |
Published in: |
Proceedings of the 15th Annual Precise Time and Time Interval Systems and Applications Meeting December 6 - 8, 1983 Naval Research Laboratory Washington, DC |
Pages: | 29 - 40 |
Cite this article: | Allan, D.W., Glaze, D.J., Gray, J.E., Jones, R.H., Levine, J., Stein, S.R., "Recent Improvements in the Atomic Time Scales of the National Bureau of Standards," Proceedings of the 15th Annual Precise Time and Time Interval Systems and Applications Meeting, Washington, DC, December 1983, pp. 29-40. |
Full Paper: |
ION Members/Non-Members: 1 Download Credit
Sign In |