Long-term geodetic product assessment derived from a VLBI transmitter on Next-Generation GNSS

Classical Very Long Baseline Interferometry (VLBI) observations are unique for the estimation of UT1-UTC and Celestial Intermediate Poles (CIPs). The innovative feature of placing a VLBI transmitter on a satellite provides additional information about Earth’s origin, the geocenter. It also enables the VLBI technique to be combined with other satellite-based techniques such as GNSS via a space tie on the common satellite. This research aims to evaluate the long-term geodetic products estimated by VLBI observations to a next-generation Global Navigation Satellite System (NextGNSS) satellite. We simulate a VLBI network comprising 20 stations including 18 current and future VLBI Global Observing System (VGOS) stations that simultaneously observed a single VLBI transmitter on a Galileo-like satellite, in conjunction with extra-galactic radio sources. Terrestrial Reference Frame (TRF) including station positions and velocities, geocenter coordinates, and the full set of Earth Orientation Parameters (EOPs) are estimated for a long-term period of three years. Subsequently, we impose no-net rotation (NNR) and no-net translation (NNT) conditions, resulting in a minimum constraint solution. Satellite observations were assumed at a ratio of 30% of the total observations. The results show that the estimated corrections in the X and Y geocenter coordinates are on the mm-level and the Z coordinate on the cm-level.