  We report the realization of a large scale gravity antenna based on
matter-wave interferometry, the MIGA project. This experiment consists in an
array of cold Rb sources correlated by a 150 m long optical cavity. MIGA is in
construction at the LSBB underground laboratory, a site that benefits from a
low background noise and is an ideal premise to carry out precision gravity
measurements. The MIGA facility will be a demonstrator for a new generation of
GW detector based on atom interferometry that could open the infrasound window
for the observation of GWs. We describe here the status of the instrument
construction, focusing on the infrastructure works at LSBB and the realization
of the vacuum vessel of the antenna.
