Multi-GNSS time transfer with CGGTTS-V2E

A software tool was developed at the Royal Observatory of Belgium for building the CGGTTS products from the RINEX observation and navigation files provided by the GNSS receivers. This software has been completely re-built in order to increase the robustness, the computation speed, and to include GPS, GLONASS, BeiDou and Galileo. The first part of the paper describes this new software tool. Then some time transfer experiments are realized for a short and a long baseline, comparing the results obtained from single-constellation with the multi-constellation solutions. We show that even with an incomplete constellation, Galileo already provides time transfer results with nearly the same quality as GPS for the short baseline, and 1.5 times better for the long baseline time link. Combining GPS and Galileo satellites furthermore improves the time transfer link with respect to the GPS-only or Galileo-only solutions, reducing the noise by a factor of about 1.4. Adding moreover BeiDou satellites in the combination gives a solution similar to the solution obtained from GPS+Galileo.