GPS All in View time transfer for TAI computation

Abstract

Since the 1980s, GPS time links have been essential to the TAI computation and, until 2006, the Common View (CV) technique has been used for this purpose. Recent advances in obtaining precise satellite orbits and clock parameters now permit us to obtain better results using another technique, which we name All in View (AV). By comparing the GPS CV and AV with the independent and more accurate TW and PPP time transfer techniques, we quantify the gain that can be obtained on a given time link. The AV technique also allows us to choose a more efficient network of GPS links between the tens of laboratories participating in TAI, which further improves the uncertainty in the access to UTC. The BIPM TAI software has been updated and the AV technique has been effectively used since the computation for the month of September 2006.