Assessing the Potential of VLBI for Satellite Orbit Determination using Simulated Observations

Abstract

The ESA Genesis mission, planned for launch in 2028/29, will carry a dedicated VLBI (Very Long Baseline Interferometry) transmitter, enabling direct VLBI observations to a satellite. This represents a major step forward, as it opens new possibilities for satellite orbit modelling based on VLBI data and may improve the accuracy and consistency of orbit determination across space-geodetic techniques.

In this study, the capability of VLBI to estimate the six orbital elements together with nine solar radiation pressure (SRP)–related dynamical parameters is assessed using simulated VLBI observations to Galileo satellites. Partial derivatives of the orbital and dynamical parameters are obtained from the ORBGEN module of the Bernese GNSS Software. The SRP accelerations are decomposed into three orthogonal directions: along the satellite–Sun direction, along the solar panel axis, and along the direction completing the right-handed coordinate system. In each of these three directions, constant and periodic empirical parameters are estimated.

The results provide insight into the sensitivity of VLBI observations to orbital and SRP parameters and demonstrate the potential of VLBI for satellite orbit determination.