Assessing the frame ties between VLBI observations to quasars and Genesis

Abstract The European Space Agency’s (ESA) Genesis mission will integrate multiple space geodetic techniques on a single satellite at an altitude of 6000 km, serving as a dynamic space geodetic observatory. Its primary goal is to significantly enhance the accuracy and stability of Terrestrial Reference Frames (TRFs). A key feature of Genesis is the dedicated Very Long Baseline Interferometry (VLBI) transmitter, which enables observations to the satellite using the existing VGOS antennas and infrastructure. Using the well-established pipeline of software modules provided by the Vienna VLBI and Satellite Software (VieVS), weekly 24-hour VLBI sessions over a five-year period, comprising observations to both quasars and the Genesis satellite, are scheduled and simulated. The subsequent analysis and derivation of TRFs allow not only for the estimation of a single set of VLBI station positions and velocities from the combined set of observations but also for the simultaneous estimation of positions and velocities from both observation types separately. This enables a comparative analysis between the combined and the separate TRFs, as well as a direct comparison between the satellite-based and quasar-based TRFs.