Absolute gravity value is requested in several domain, from geophysics to metrology with the implementation of the kilogram. Since 2003, SYRTE has developed a state-of-the-art cold atom gravimeter (CAG), based on atom interferometry technics. It uses free-falling $^{87}$Rb atoms, which experience a sequence of two-photons Raman pulses driven by counter-propagating vertical lasers. The atom...