“…Steelman and Endres (2011) reported accuracy levels after analysing the behaviour of some petrophysical relationships for several types of geological materials and antenna frequencies ( Table 2). The early-time technique estimates GPR θ without v while changes in amplitude attributes of the combined air wave and ground wave of the reflected signal collected through common offset configurations are used to map ε r (Prado et al, 2011;Ferrara et al, 2013;Algeo et al, 2016).…”