Spacecraft VLBI and Doppler tracking: algorithms and implementation

TL;DR

This paper demonstrates that multi-station VLBI can accurately determine spacecraft positions with an internal rms accuracy of 0.1 mas, improving planetary mission tracking capabilities through advanced algorithms and processing pipelines.

Contribution

The paper introduces a software pipeline for near-field VLBI observations and validates its effectiveness with ESA Venus Express data, achieving high-precision spacecraft tracking.

Findings

Achieved 0.1 mas internal rms accuracy in spacecraft position determination.

Systematic effects can cause offsets up to 1 mas, but are mitigable.

Method demonstrates potential for future planetary mission navigation.

Abstract

We present the results of several multi-station Very Long Baseline Interferometry (VLBI) experiments conducted with the ESA spacecraft Venus Express as a target. To determine the true capabilities of VLBI tracking for future planetary missions in the solar system, it is necessary to demonstrate the accuracy of the method for existing operational spacecraft. We describe the software pipeline for the processing of phase referencing near-field VLBI observations and present results of the ESA Venus Express spacecraft observing campaign conducted in 2010-2011. We show that a highly accurate determination of spacecraft state-vectors is achievable with our method. The consistency of the positions indicates that an internal rms accuracy of 0.1 mas has been achieved. However, systematic effects produce offsets up to 1 mas, but can be reduced by better modelling of the troposphere and ionosphere and closer target-calibrator configurations.