GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 3.2 GNGTS 2024 Moreover, looking at the HH and VV channels separately, the resultng images are clearer than the one with all the channels together. Looking at the lower panels, one can appreciate the diference when using only a subset of the 32 VV dipoles: 8 dipoles (12 cm between-lines resoluton), 4 dipoles (25 cm) and 2 dipoles (50 cm). In this test site, the 12-cm image and even the 25-cm one, do not difer too much from the all-VV (4cm) image. Instead, the 50-cm-resoluton image, which have a resoluton similar to surveys performed with single-antenna GPR systems, is much less clear, even if the major structures are stll roughly detected. Fig. 1 – Comparison between 1.25 m depth-slices from 3D data volumes created using 6 diferent subsets of the total 32 channels of the Stream C: : upper panels) all the 32 channels, VV+HH (spacing about 3 cm), only the VV channels (spacing about 4 cm), only the HH channels (spacing about 10 cm); lower panels) diferent subsets of the VV channels with spacing of about 12, 25 and 50 cm respectvely. One can argue if the total amount of channels in the Stream C is really necessary to perform an archaeological investgaton. Surely, the presence of both HH and VV dipoles seems important, and in the absence of both, the survey should be carried out in a grid shape, instead of a simpler boustrophedon path, to avoid missing some important targets. However, the depth-slice obtained using only 4 out of 23 channels is not much worse than the total one. Probably, lighter GPR multchannel systems including 4 VV channels and 4 HH channels could be an optmal compromise