Ground penetrating SAR buried landmine focusing in ground-plane
Airborne or vehicle-borne Ground Penetrating Synthetic Aperture Radar (GPSAR) can image buried landmines from a safe standoff distance. Traditional image formation, for example, Back-Projection (BP), focuses the image in the slant-plane without considering the refraction of air-soil interface and soil dispersion effects on subsurface landmines. Furthermore, geometric correction has to be performed to map the image from the slant-plane onto the ground-plane to get the ground truth. In this paper, a modified BP, denoted as Ground-Plane BP (GPBP), and its associated post-filter are proposed to form the image directly in the ground-plane with refraction and dispersion effects compensation. The proposed GPBP and its post-filter compensation scheme are validated using real data collected by the Rail-GPSAR system in terms of azimuth resolution and locating accuracy.