Accession Number : ADP004573

Title :   Recent Improvements in the Atomic Time Scales of the National Bureau of Standards,

Corporate Author : NATIONAL BUREAU OF STANDARDS BOULDER CO TIME AND FREQUENCY DIV

Personal Author(s) : Allan,D. W. ; Glaze,D. J. ; Gray,J. E. ; Jones,R. H. ; Levine,J.

Report Date : 02 APR 1984

Pagination or Media Count : 12

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 UTV(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 to the minus 14th power 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). Fourth, a significantly improved working time and frequency reference is readily available. And fifth, a very stable frequency reference is obtained by using all of the clocks available in the NBS clock ensemble.

Descriptors :   *TIME STANDARDS, ATOMIC CLOCKS, MEASUREMENT, CALIBRATION

Distribution Statement : APPROVED FOR PUBLIC RELEASE