Accession Number : ADP009122

Title :   An Algorithm for the Italian Atomic Time Scale,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GREENBELT MD GODDARD SPACE FLIG HT CENTER

Personal Author(s) : Cordara, F. ; Vizio, G. ; Tavella, P. ; Pettiti, V.

Report Date : 02 DEC 1993

Pagination or Media Count : 12

Abstract : During the past twenty years, the time scale at the IEN has been realized by a commercial cesium clock, selected from an ensemble of five, whose rate has been continuously steered towards UTC to maintain a tong term agreement within 3 x 10-13. A time scale algorithm, suitable for a small clock ensemble and capable of improving the medium and long term stability of the IEN time scale, has been recently designed taking care of reducing the effects of the seasonal variations and the sudden frequency anomalies of the single cesium clocks. The new time scale, TA(IEN), is obtained as a weighted average of the clock ensemble computed once a day from the time comparisons between the local reference UTC(IEN) and the single clocks. It is foreseen to include in the computation also ten cesium clocks maintained in other Italian laboratories to further improve its reliability and its Long term stability. To implement this algorithm, a personal computer program in Quick Basic has been prepared and it has been tested at the IEN time and frequency laboratory. The paper reports on the results obtained using this algorithm on the real clocks data relative to a period of about two years.

Descriptors :   *ATOMIC CLOCKS, *CALIBRATION, AGREEMENTS, ALGORITHMS, ANOMALIES, CESIUM, COMPARISON, COMPUTATIONS, COMPUTER PROGRAMS, MICROCOMPUTERS, RELIABILITY, SCALE, SEASONAL VARIATIONS, STABILITY, TIME, ITALY, WEIGHTING FUNCTIONS.

Subject Categories : Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE