The atomic time scale at the Time Service Division of the National Observatory in Rio de Janeiro (ONRJ) has been carried out by commercial cesium clocks. The UTC (ONRJ) time scale based on a single commercial cesium clock selected from the ensemble of clocks is not suitable to attain the bounds of uncertainty recommended by the ITU-R and by the CCTF. The recommendation has suggested to the national time primary laboratories to coordinate with UTC within plusmn0.lmus. The development of atomic time scale system was divided in two parts: the construction of an automated data acquisition system and the implementation of the time scale algorithm that generated a time scale based on the clock ensemble. The present work will describe the atomic time scale system and report the results obtained using real clocks data from September 27, 2004 to August 15, 2005
[1]
B. Guinot,et al.
Some Properties of Algorithms for Atomic Time Scales
,
1987
.
[2]
T. Weissert,et al.
AT2, a new time scale algorithm : AT1 plus frequency variance
,
1991
.
[3]
A. G. Mungall.
Atomic Time Scales
,
1971
.
[4]
M. A. Weiss,et al.
A study of the NBS time scale algorithm
,
1989
.
[5]
D. W. Allan,et al.
Time and Frequency (Time-Domain) Characterization, Estimation, and Prediction of Precision Clocks and Oscillators
,
1987,
IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.
[6]
Patrizia Tavella,et al.
Comparative Study of Time Scale Algorithms
,
1991
.