AVIOSAR-580 campaign on the Matera test site, bare soil sigma0 determination in X band

This paper describes the activity performed in the framework of the AVIOSAR 580 Italian campaign. The research was aimed at testing the reliability of the Geometrical Optics model in order to estimate the backscattering coefficient dependence on surface roughness parameters. Bare soil fields have been considered. On the Matera test site the ground truth was collected to describe the physical and geometrical characteristics of 38 homogeneous fields. Model data are compared with the ones obtained from X band and VV polarization by the HUTSCAT scatterometer and the CCRS airborne SAR, respectively at the incidence angles of 45° and about 62°. The SAR data were calibrated using both corner reflectors and extended natural targets. The backscatter variability due to surface roughness has been analyzed. A good agreement has been found between theoretical prediction and experimental data only for rough surfaces characterized by a high value of the root mean square slope profile (m). A threshold value for m, depending on the incidence angle, has been found.