  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.
