These Journées 2019 are sponsored by Paris observatory, CNRS-INSU, GRAM and co-sponsored by the International Astronomical Union (IAU) and the International Association of Geodesy (IAG).
They are in the direct continuation of the recurrent Journées which have been organized with success during more than two decades.
The main purpose of this international meeting is to provide a forum for advanced discussions in the fields of astrometry, Earth rotation, space and time reference systems and frames, solar system dynamics and ephemerides, time metrology and space navigation.
A particular attention will be given to the recent progress made in the fields of astrometry due to the exploitation of the Gaia mission and to the recently adopted ICRF3, as well as to the celebration of the Centenary of the IAU commission "Rotation of the Earth", with scientific and historic contributions.
A session will be dedicated to B.Kolaczek and J.Kovalevsky achievements.