A Linear Inverse Scattering Algorithm for Radar Imaging in Multipath Environments

This letter deals with the electromagnetic imaging in the presence of multipath propagation of interest for through-wall and urban sensing scenarios. The 2-D tomographic approach here presented combines a linear inverse scattering model, based on the Kirchhoff approximation, with the finite-difference time-domain (FDTD) technique. In particular, FDTD is exploited to evaluate the incident field and Green's function in noncanonical scenarios, so that the kernel of the linear integral equation is completely built. After, an inversion scheme based on the truncated singular value decomposition is applied to obtain a regularized solution of the problem. Numerical results demonstrate that the proposed approach yields well-focused images free of multipath ghosts, thus allowing to discriminate the actual target position. Moreover, it permits to highlight the capabilities offered by multipath exploitation such as improved crossrange resolution and detection of targets in the non-line-of-sight region of the radar.