On the possibility of getting traceable time and frequency measurements via GNSS receivers

Abstract

The realization of Coordinated Universal Time, one of the tasks of the International Bureau of Weights and Measures, relies on a network of international time links which currently is organized in a star-like scheme that links all contributing laboratories. GPS signal reception is the technique most widely employed by the laboratories. The PTB currently plays a unique role in the process due to its function as the central pivot in the time transfer between the participating laboratories. We discuss how the PTB meets its obligations to the international timekeeping community as well as to its users in Germany. In its role as an National Metrology Institute (NMI), PTB is entrusted with the realization and dissemination of legal time in Germany. The services were offered to the public support measurements and timing applications traceable to the national and international standards to be made in calibration laboratories and in many industrial sectors. We thus discuss the meaning and definition of traceability, how different GNSS systems can be used to establish traceability and their performance in doing so.

Improved performance of BDS-3 time and frequency transfer based on an epoch differenced model with receiver clock estimation

“…All receivers were manufactured from Septentrio (Belgium), whose equipments are widely used in time and frequency determination. Considering that the station PTBB, associated with the Physikalisch-Technische Bundesanstalt (PTB), was usually set as the central station in the practical work of the time and frequency transfer, we used it as a reference station in the experiment [26]. Therefore, time links were formed, denoted by UTC(Lab2)-UTC(Lab1) or Station1-Station2, referring to the basic quantity that was generally used to analyze the performance of the time and frequency transfer.…”

Traceable frequency measurements with counters

“…Significant documentation on traceability to US standards was published earlier [21,22]. Those form together with previous papers of this work's authors [23][24][25] the foundation of this report. Based on already available guidelines [26,27] we illustrate in the next section a full scheme for traceable frequency measurements with counters in a calibration laboratory.…”

“…In this work, PTB's reference time scale UTC(PTB) plays this part. As already described in previous publications [23,25], monitoring results are published in the PTB TSB and the operator should collect them for his own analysis of the contributing uncertainties. All three parts together form the basis for the uncertainty budget, which is developed step by step in the subsequent sections.…”

“…From the observations, daily averages of UTC(PTB)-GPS time are computed and reported in the PTB TSB. Its current format is described in [25] (for availability information see section 2). How the data are prepared for the TSB is described in [24] and here summarized as follows.…”