CIPM MRA COMPARISON REPORTS

Under the framework of the Gulf Cooperation Council Standardization Organization's Regional Metrology Organization (GULFMET), a supplementary comparison of UTC time scales was conducted among national metrology institutes from Saudi Arabia (SASO-NMCC), Türkiye (TÜBITAK UME), Uzbekistan (UzNIM), Egypt (NIS), the United Arab Emirates (EMI), and Azerbaijan (AzMI). The comparison employs the GNSS Common-View technique based on GPS L3P data to evaluate the performance and alignment of the participating UTC(k) realizations and to strengthen regional traceability to UTC. This exercise represents a cross-RMO comparison coordinated by GULFMET, involving institutes affiliated with EURAMET, COOMET, and AFRIMETS. The study presents the comparison methodology, measurement results, and experience gained from organizing a regional time-scale comparison, emphasizing the importance of interregional cooperation in reinforcing global time and frequency networks. In addition to the primary comparison objectives, an extended set of statistical analysis methods was applied to systematically profile the participating systems. Time-domain metrics such as mean offset, standard deviation, and linear drift were used to distinguish short-term stability from long-term frequency behavior using a common reference time scale (UTCr). These methods provide a consistent and transparent framework for comparative performance assessment across laboratories. The results demonstrate both the technical outcomes of the comparison and the value of enhanced statistical profiling for characterizing time-scale behavior. The work also supports the development of improved data handling, analysis, and reporting practices within GULFMET, contributing to a more integrated and collaborative regional time-keeping community.

Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCTF, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).