Fig. 1From: Optimal distribution of VLBI transmitters in the Galileo space segment for frame tiesIllustration of a Galileo satellite observed with VLBI radio telescopes and GNSS antennas on the ground. This concept will allow the transfer of the space tie to the local tie at the Earth surface. Moreover, the station coordinates of the radio telescope can also be determined from observations to quasars, thereby realizing the frame tieBack to article page