PTB’s Time and Frequency Activities In 2008 And 2009

M. Rost, A. Bauch, J. Becker, T. Feldmann, D. Piester, T. Polewka, D. Sibold, and E. Staliuniene

Abstract:	The Physikalisch-Technische Bundesanstalt (PTB) maintains the German national time scale, disseminates time and frequency for both business and general public, and undertakes research to improve its facilities. This report covers the activities of PTB’s Time Dissemination Working Group during 2008 and 2009. PTB’s time scale UTC (PTB) is based on the primary clock CS2 and an associated phase micro-stepper to keep the time scale in reasonable agreement with UTC. CS2 and the other primary standards, CS1, CSF1, and CSF2, are part of PTB’s ensemble of atomic clocks whose data are provided for the computation of TAI. During 2009, the commercial clocks have been moved step by step to a new clock room with improved operational conditions and state-of-theart cabling. A broad range of satellite time-transfer equipment is being operated to enable time scale comparisons with other institutes all over the world. Single/multi-channel GPS receivers as well as so-called geodetic receivers enable frequency and time transfer with the state-of-the-art evaluation techniques (C/A code, P3, carrier phase, PPP). Two-way satellite time and frequency transfer (TWSTFT) is made routinely with several stations in Europe, the US, and Asia. Several calibration campaigns have been performed, partly with substantial support of USNO and BIPM, which allowed verification of the time-transfer uncertainty using PTB’s current equipment. PTB provides services to disseminate time and frequency within Germany. The most prominent example is the low-frequency transmitter DCF77, which is widely used. In 2009, PTBlooks back on 50 years operation of this service. Other time services are the NTP-servers as well as the telephone time service to synchronize computer via Internet or modem connection,respectively. The capability of the NTP infrastructure was enhanced by the introduction of an additional NTP server. PTB acts as one of the four so-called UTC (k) laboratories cooperating with the future Galileo Time Service Provider. In this framework, its clock-monitoring and measurement systems have been refurbished and upgraded, looking forward to a long-term involvement in thisactivity. PTB has also supported the realization of one of Galileo’s Precise Timing Facilities, and a status of this activity will be provided.
Published in:	Proceedings of the 41st Annual Precise Time and Time Interval Systems and Applications Meeting November 16 - 19, 2009 Hyatt Regency Tamaya Resort Santa Ana Pueblo, New Mexico
Pages:	197 - 214
Cite this article:	Rost, M., Bauch, A., Becker, J., Feldmann, T., Piester, D., Polewka, T., Sibold, D., Staliuniene, E., "PTB’s Time and Frequency Activities In 2008 And 2009," Proceedings of the 41st Annual Precise Time and Time Interval Systems and Applications Meeting, Santa Ana Pueblo, New Mexico, November 2009, pp. 197-214.
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