The TWSTFT links circling the world

Two-way satellite time and frequency transfer (TWSTFT), other than the GNSS related techniques, has been one of the most precise time transfer methods. Telecommunication laboratories (TL) has devoted to set up the TWSTFT links with several important Laboratories and achieved the goal of establishing TWSTFT links circling the world. The numerical results of several direct and connected TWSTFT links will be demonstrated in the paper. The results show that a well maintained connected TWSTFT links, even with more than 2 relay stations, can still have good performance.