During the period October 30 – November 02 2023, the International Timing and Sync Forum 2023 was held in Antwerp, Belgium, at which the representative of the IMBIH was a speaker on the topic “Towards time and frequency dissemination as a national critical infrastructure in Bosnia and Herzegovina”. We described first realization of a fiber-optical link devoted to the distribution of time and frequency reference signals, synchronized with UTC(IMBH), to end user in Bosnia and Herzegovina. 

Critical infrastructure like electric power grids, telecoms, finance sector, etc. rely on Global Navigation Satellite Systems (GNSS) for accurate time or synchronization, as reliable sources of accurate time or synchronization under normal conditions. However, the disadvantage is that the time transfer from the satellites to the user is quite vulnerable to intentional and non-intentional disturbances. Furthermore, GNSS as a single source of time is questionable for use in critical applications. As an alternative to GNSS, a UTC local timescale realization combined with robust dissemination network are rapidly implemented solutions in the majority of developed European countries.

Institute of Metrology of Bosnia and Herzegovina (IMBIH) is responsible for the realization of national time scale UTC(IMBH) and participate in International time scale (UTC) computation. Our system is based on several high performance cesium atomic clocks, metrology grade time transfer  and dissemination equipment, providing highly accurate, stable and traceable time scale continuously for a years. The time transfer system in this demonstration case is based on commercial dark fibers using the White Rabbit (WR) protocol (IEEE1588-2019 with high accuracy profile). We demonstrated long-haul GNSS independent fiber-optical link with the capability of sub nanosecond time dissemination accuracy and frequency stability order of cesium atomic clock, which operates continuously for over a year without interruptions, overwhelming performance of GNSS systems. Implemented solution can be basis for robust multi-reference time and frequency source of the end users, mitigating risks of GNSS vulnerabilities. This system could be integrated in a future development of a larger national infrastructure used as GNSS independent network for timing and synchronization to variety of industrial, government and scientific users across the country.

International Timing and Sync Forum is one of the world's largest conferences on this topic, gathering over 350 world-class speakers, NMIs, manufacturers, system implementers, end-users, and standardization bodies. This was also an opportunity to improve existing ones and initiate numerous new collaborations and projects in this area.