Fast and accurate shadow region imaging algorithm using range derivatives of doubly scattered signals for UWB radars

UWB (Ultra Wideband) radars have great promise for near field sensing systems, holding its high range resolution. It is particularly suitable for robotic or security sensors that must identify a target in optically blurry visions. Some recently developed radar imaging algorithms proactively employ multiple scattered components, which can enhance an imaging range compared to synthesizing a single scattered component. We have already proposed the SAR (Synthetic Aperture Radar) method considering a double scattered, which successfully expanded a reconstructible range of radar imagery with no preliminary knowledge of target or surroundings. However, this method requires an intensive computation and its spatial resolution is insufficient for clear boundary ex traction such as edges or specular surfaces. As a substantial solution, this paper proposes a novel shadow region imaging algorithm based on a range derivative of double scattered signals. This new method accomplishes high-speed imaging, including a shadow region without any integration process, and enhances the accuracy with respect to clear boundary extraction. Some results from numerical simulations verify that the proposed method remarkably decreases the computation amount compared to that for the conventional method, enhancing the visible range of radar imagery.