The recent activities on two-way satellite time transfer AT TL

The researches of two way satellite time and frequency transfer (TWSTFT) at TL are very active in the recent years. In Asia Pacific Rim region, TL has joined the Asia-Pacific networks (being organized and sponsored by CRL) since June 2000, and performed the C-band experiments of NML(Australia)-TL and NIST(USA)-TL from September 2002 to April 2003. Moreover, the Ku-band TWSTFT experiments of CRL-TL, CRL-NML and NML-TL links, using PAS-8 satellite, are in progress. For the intercontinental cases, the major time transfer link between Europe and Asia is the PTB-CRL GPS CV single channel currently. The time-transfer connection between North America and Asia is also not well planned. In order to enhance the time transfer connection between Europe and Asia, TL and VSL (the Netherlands) have cooperated and succeeded in the set up of the first Europe-Asia TWSTFT link, VSL-TL link, and the regular experiments have been performed from March 2003. For the cooperation between North America and Asia, the USNO-TL link is also under planning. The recent activities and the future works on TWSTFT at TL will be illustrated in this paper.