Generation of UTC(PTB) as a fountain-clock based time scale

The Physikalisch-Technische Bundesanstalt (PTB) has substantially improved the quality of its local time scale UTC(PTB), which is the national realization of the international time reference Coordinated Universal Time (UTC). It serves as the basis for PTB's time services, for local clock comparisons and for international time comparisons. Since February 2010 UTC(PTB) has been realized using an active hydrogen maser (AHM) steered in frequency via a phase micro-stepper according to an algorithm which combines the frequency comparison data between the AHM and primary and commercial caesium clocks of PTB. Thereby the long-term stability and accuracy of PTB's primary clocks, in particular its fountain clock CSF1, were combined with the short-term frequency stability of the AHM. CSF1 data were used to calculate the steering on all but six days during 15 months. During the time between July 2010 and July 2011, the time difference between UTC(PTB) and UTC was always less than 6?ns and the monthly mean rate differences never exceeded 0.16?ns per day.

[1]  Gianna Panfilo,et al.  A new prediction algorithm for EAL , 2011, 2011 Joint Conference of the IEEE International Frequency Control and the European Frequency and Time Forum (FCS) Proceedings.

[2]  E. Peik,et al.  Stray-field-induced quadrupole shift and absolute frequency of the 688-THz {sup 171}Yb{sup +} single-ion optical frequency standard , 2009 .

[3]  Andreas Bauch,et al.  Metrology of Time and Frequency , 2011 .

[4]  Andreas Bauch,et al.  Advanced GPS-Based Time Link Calibration with PTB's New GPS Calibration Setup , 2010 .

[5]  Patrizia Tavella,et al.  The evaluation of uncertainties in [UTC − UTC(k)] , 2006 .

[6]  Andreas Bauch,et al.  The PTB primary clocks CS1 and CS2 , 2005 .

[7]  Andreas Bauch,et al.  Uncertainty evaluation of the atomic caesium fountain CSF1 of the PTB , 2001 .

[8]  F. Cordara,et al.  Fidelity - Progress Report on Delivering the Prototype Galileo Time Service Provider , 2007, 2007 IEEE International Frequency Control Symposium Joint with the 21st European Frequency and Time Forum.

[9]  F. Luongo,et al.  Timing infrastructure for Galileo System , 2006, Proceedings of the 20th European Frequency and Time Forum.

[10]  G. Petit.  Use of Primary Frequency Standards for Estimating the Duration of the Scale Unit of TAI , 1999 .

[11]  R. Wynands,et al.  Uncertainty evaluation of the caesium fountain clock PTB-CSF2 , 2010 .

[12]  Pierre Héroux,et al.  Precise Point Positioning Using IGS Orbit and Clock Products , 2001, GPS Solutions.

[13]  A. Bauch,et al.  A new realization strategy for the time scale UTC(PTB) , 2004, Proceedings of the 2004 IEEE International Frequency Control Symposium and Exposition, 2004..

[14]  Peter Whibberley,et al.  Local representations of UTC in national laboratories , 2011 .

[15]  Gianna Panfilo,et al.  Timescales at the BIPM , 2011 .

[16]  Dirk Piester,et al.  New realization strategy for UTC(PTB) , 2011, 2011 Joint Conference of the IEEE International Frequency Control and the European Frequency and Time Forum (FCS) Proceedings.

[17]  Otto Koudelka,et al.  Time transfer with nanosecond accuracy for the realization of International Atomic Time , 2008 .

[18]  Andreas Bauch,et al.  The Atomic Caesium Fountain CSF1 of Ptb , 2002 .