ABSTRACT
In their early days of development (1970s and 1980s), subsurface radars were considered an electromagnetic technique for detection of subsurface objects at depths of a few meters. This was possible for the frequency range of 100-500 MHz that was accessible at the time [1,2]. Depth resolution in this band was restricted to 0.5-1 m, and the main media under consideration at that time were soils and glacial ice. These applications gave this early type of radar the name ground-penetrating radar (GPR). The abbreviation is still in wide use despite the fact that modern subsurface radars have much wider areas of application, perhaps deserving the more accurate name of materials-or surface-penetrating radar [3].
