Investigations on Array Element Spacing of a Synthetic Aperture for Subsurface Imaging

The influence of the element spacing of an antenna array that forms a synthetic aperture is investigated in the context of subsurface imaging. Focusing techniques based on synthetic aperture radar are used in subsurface radar for increasing the lateral resolution, i.e. the resolution of the buried objects in a horizontal plane parallel to the air-soil interface. In this work an exact three dimensional focusing technique that regards the refraction of the two-layered geometry is applied on the measured radar raw data for the image reconstruction of the buried scatterers. In order to investigate the effect of the element spacing of the synthetically generated array on the reconstructed image different measurement scenarios in a realistic environment have been performed. The experimental results show a strong dependence of the discrete element spacing of the antenna array on the quality of the reconstructed images.