Continuous free fall acceleration determination for the LNE Watt balance

Watt balance projects aim at linking the kilogram definition to the Planck constant. The weighting of the mass involved requires a determination of the acceleration g with an uncertainty better than 10
⁻⁸
. We report on our studies and developments for the LNE Watt balance project and focus on continuous absolute g measurement obtained with an atomic and/or a superconducting gravimeter and a dedicated gravimetric site.