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

TL;DR

This paper improves the orbit determination accuracy of the RadioAstron Space VLBI mission by combining advanced dynamical modeling with multi-station Doppler tracking, leading to more precise scientific observations.

Contribution

It introduces a sophisticated orbit reconstruction method that significantly enhances the accuracy of RadioAstron's orbit determination using multi-station Doppler data and dynamical modeling.

Findings

Orbit accuracy improved from ~600 m to several tens of meters.

Velocity accuracy enhanced from ~2 cm/s to mm/s.

Enhanced orbit data improves VLBI correlation and scientific output.

Abstract

The accuracy of orbit determination has a strong impact on the scientific output of the Space VLBI mission RadioAstron. 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. 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. 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.