The Reference and Fiducial gravity networks in Italy

The Italian area is affected by on-going deformations and/or mass transfers both of geophysical and human origin, which act at very different temporal scales and modify significantly the gravity field over time. The current Italian gravity database contains gravimetric measurements taken on land and sea by various Research Institutions and Services. Data were acquired at very different epochs, with different instruments, some now obsolete and mostly lacking inter-comparison, also with non-uniform operational procedures of data acquisition and analysis. Thus, these data are not homogeneous and do not represent an updated image of the Italian gravity field. This paper shows the main steps followed toward the realization of a new reference network for absolute gravity in the Italian area. The choices are in line with the resolutions approved by the International Association of Geodesy during its 2015 General Assembly. The goal is to update the existing absolute gravity network by adding gravity stations according to the new standards to align this infrastructure to the highest level of precision and accuracy. Based on that, an overall revision of the Italian gravity database will be possible thus leading to a better estimate of the gravity potential.