A method for monitoring surface deformations of a scenario by means of differential interferometry technique, including the steps of prearranging a radar sensor having a transmitting antenna and a receiving antenna arranged to transmit and acquire radar signals, the radar sensor arranged to move along a planar trajectory γ having centre O; defining a reference system S having origin in the centre O; acquiring by SAR technique the scenario by means of handling the radar sensor along the planar trajectory γ, the radar sensor being configured so that the radiation pattern of the antennas is oriented radially with respect to the centre O, the acquisition occurring at points of acquisition si arranged on the trajectory γ, the three-dimensional position of each target point ti being definable by means of spherical coordinates (ρi,θi,βi).