a method and installation for ground illumination by means of electromagnetic radiation generated by an aerial simulator coupled to the ground and for calculation of the dielectric constant and conductivity of the ground from said radiation are described . radiation is transmitted in form of an electromagnetic pulse having predetermined characteristics from an aerial simulator of the horn type , the characteristics of the pulse are sensed at a point in the illuminated area and the dielectric constant and the conductivity of the ground are calculated from the detected values . the apparatus constituting the simulator comprises at least two conductive layers e . g . of conductive wires , united on one side to form the horn , and ending up on the opposite side at the ground where they are extended by a buried structure and on that side where they are united , in a connector to provide connection with pulse generating and measurement means .