Characterizing and correcting media-induced focus errors in SAR imagery

摘要: Recently, considerable attention has been directed to the use of airborne synthetic-aperture radar (SAR) for detecting both large and small underground objects. The reconstruction of images of buried objects from SAR data, however, often relies on assumptions and algorithms developed in the context of free-space radar propagation. Although in some cases the implicit assumption of free-space propagation can lead to acceptable results, in other important cases it will result in severe degradation to images of underground objects. In this paper we investigate the conditions under which significant improvements to image quality result if proper account is taken of the detailed effects of the soil medium on radar wave propagation. These effects are analyzed both in terms of the refraction of plane waves and via reference to general analytic solutions to Maxwell's equations. Quantitative predictions of the improvement in …