摘要：Context. The closest ever fly-by of the Martian moon Phobos, performed
by the European Space Agency’s Mars Express spacecraft, gives a unique opportunity to
sharpen and test the Planetary Radio Interferometry and Doppler Experiments (PRIDE)
technique in the interest of studying planet–satellite systems.
Aims. The aim of this work is to demonstrate a technique of providing
high precision positional and Doppler measurements of planetary spacecraft using the Mars
Express spacecraft. The technique will be used in the framework of Planetary Radio
Interferometry and Doppler Experiments in various planetary missions, in particular in
fly-by mode.
Methods. We advanced a novel approach to spacecraft data processing
using the techniques of Doppler and phase-referenced very long baseline interferometry
spacecraft tracking.
Results. We achieved, on average, mHz precision (30 μm/s at a 10 s
integration time) for radial three-way Doppler estimates and sub-nanoradian precision for
lateral position measurements, which in a linear measure (at a distance of 1.4 AU)
corresponds to ~50 m.
关键词：techniques: interferometric;techniques: miscellaneous;methods: data analysis;astrometry
