Potential of VLBI for Orbital and Solar Radiation Pressure Parameter Estimation

Abstract

The Genesis mission, scheduled for launch by the European Space Agency (ESA) in 2028, will carry a dedicated VLBI (Very Long Baseline Interferometry) transmitter. This mission represents a significant advancement, as it will enable direct VLBI observations of a satellite, opening new possibilities for satellite orbit modelling based on VLBI data and potentially improving the accuracy and consistency of orbit determination across different space-geodetic techniques. In this study, the potential of VLBI to estimate the six orbital elements together with nine solar radiation pressure (SRP)–related dynamical parameters is investigated using simulated VLBI observations. The analysis employs partial derivatives with respect to the dynamical parameters obtained from the ORBGEN module of the Bernese GNSS Software. The SRP-induced accelerations are decomposed into three orthogonal directions: (a) along the satellite to the Sun direction, (b) along the satellite’s solar panel axis, and (c) along the direction completing the right- handed coordinate system. Accordingly, the accelerations are parameterized by three components in each direction, resulting in a total of nine SRP parameters. Furthermore, the study examines the impact of geocentre estimation on the determination of both the orbital elements and the SRP parameters, providing insight into the interplay between global reference frame parameters and satellite dynamics.