Optimal requirements for determining frame ties using VLBI observations to satellites

This presentation shows the best requirements for estimating station coordinates using VLBI observations to Galileo satellites. The plan to equip some Galileo satellites with VLBI transmitters raises three main questions: How many satellites need to be equipped with a VLBI transmitter (VT) in the Galileo space segment to ensure station coordinates are sufficiently accurate. How should these satellites be spread across the three planes of Galileo and what is the best balance between observing satellites and quasars within a schedule.