A new TWSTFT station in Warsaw

This year, the final works on launching two-way satellite time and frequency transfer (TWSTFT) station in Warsaw are going to be completed. The facility of Central Office of Measures (GUM), organization responsible for maintaining the Polish realization of the international Universal Coordinated Time (UTC(PL)) is located in the center of city and is surrounded by a number of high buildings. Therefore it was difficult to establish in GUM directly TWSTFT station. Based on many years of close cooperation between National Institute of Telecommunications (NIT) and GUM the decision of placing TWSTFT station at NIT has been made, because NIT is located outside of strict city center and the antenna view is much better. The optical time transfer system (OTTS) to connect GUM and NIT is used. The length of the fiber optic line is about 28 km. Until now, the line was used for the purpose of continuous time comparison between the two organizations, so the entire fiber optic part of time transfer had to be redesigned to support two parallel transmissions. This paper aims to outline the status of the new TWSTFT station in Warsaw (at NIT-GUM) and the methods used to resolve some of the problems encountered.