  The IAU/IUGG Working Group on "Nutation for a non-rigid Earth", led by
V\'eronique Dehant, won the European Descartes Prize in 2003, for its work
developing a new model for the precession and the nutations of the Earth. This
model (MHB2000, Mathews et al. 2002) was adopted by the IAU (International
Astronomical Union) during the General Assembly in Manchester, in 2000. It is
based (i) on some improvements for the precession model (with respect to the
previous one of Lieske et al. 1977) owing to the VLBI technique, and (ii) on a
very accurate nutation model, close to the observations. With this prize, the
Descartes nutation project could offer for international scientists some
grants, to be used for further improvements of the precession-nutation Earth
model. At the IGG (Institute of Geodesy and Geophysics), with the OCCAM 6.1
VLBI analysis software and the best data and models available, we re-analyzed
the whole VLBI sessions available (from 1985 till 2005) solving for the Earth
Orientation Parameters (EOP). In this paper we present the results obtained for
the EOP and more particularly for the nutation series. We compare them with the
other IVS analysis centers results, as well as with the IVS combined EOP series
from the analysis coordinator. The series are in good agreement, except for the
polar motion coordinates that show a shift with respect to the other ones and
that we discuss here. Finally, we analyse the nutation series in the framework
of the free core nutation (FCN) study and modelisation.
