Remote Fiber Optic Connected Station for Two-Way Satellite Time and Frequency Transfer Method

The National Institute of Telecommunications (NIT), in cooperation with the Central Office of Measures (GUM), has established a station for two-way satellite time and frequency transfer in 2018. Firstly, comparisons were carried out within the European−Asian group on various satellites (ABS-2A, E80) and from early 2023 in the European−American group on the Telstar T-11N satellite. The main part (reference atomic clock) of the system is located in GUM, and the satellite station is located in NIT. These two locations are connected with a ≈ 34 km single-mode fiber and a dedicated transmission system. Such a solution is uncommon for this type of comparison. The station took part in the calibration campaign organized by the National Metrology Institutes (NMI) all over Europe in order to verify the parameters of the whole transfer system and its accuracy time and frequency transfer. In this paper, we describe the station's technical solutions and analysis of measurement and calibration results, thus confirming the correctness of the station's operation and enabling the use of the presented solutions for international transfer of UTC(PL) — the main Polish local realization of Universal Coordinated Time determined in GUM and being the source for legal time in Poland.