RadioAstron as a target and as an instrument: Enhancing the Space VLBI mission's scientific output

Context. The accuracy of orbit determination has a strong impact on the scientific output of the Space VLBI mission RadioAstron.
Aims: The aim of this work is to improve the RadioAstron orbit reconstruction by means of sophisticated dynamical modelling of its motion in combination with multi-station Doppler tracking of the RadioAstron spacecraft.
Methods: The improved orbital solution is demonstrated using Doppler measurements of the RadioAstron downlink signal and by correlating VLBI observations made by RadioAstron with ground-based telescopes using the enhanced orbit determination data.
Results: Orbit determination accuracy has been significantly improved from ~600 m in 3D position and ~2 cm/s in 3D velocity to several tens of metres and mm/s, respectively.