GINGER - A terrestrial experiment to verify the Lense-Thirring effect or possible deviations from General Relativity

After reviewing the signal to be expected from a ring laser of convenient size, located on earth, the project of a three-dimensional array of ring lasers named GINGER is presented. The sensitivity analysis is discussed, stressing that the available techniques for research lasers do allow for the detection of general relativistic eects originated by the mass and the angular momentum of the earth. The project is under development at the Gran Sasso National Laboratories of the INFN in Italy. Two intermediate instruments in the road towards the full GINGER have been built, one in Pisa (GP2) and one at the Gran Sasso (GINGERino). They are being used to validate the dynamical control of the geometry and to characterize the site allotted to the experiment.