Shadow region imaging algorithm using array antenna based on aperture synthesis of multiple scattered waves for UWB radars

Ultra-wide band (UWB) pulse radar has a definite advantage over optical ranging techniques, as to applicability to the harsh optical environment, such as the dark smog, or strong back-light. We have already proposed the extended Synthetic Aperture Radar (SAR) algorithm employing the multiple scattered waves, which aims at enhancing the reconstructible region of the target boundary including the shadow. However, it still suffers from the shadow region in the case of the target with a sharp inclination or deep concave boundary, because it assumes the antenna scanning whose real aperture size is too small. To resolve this difficulty, this paper proposes an extension algorithm using the array antenna model. While this extension is quite simple, the effectiveness of the proposed method is nontrivial regarding to the expansion of the imaging range. The results from numerical simulations verify that our method remarkably enhances the visible range of target surfaces without a priori knowledge of target shapes or a preliminary observation of its surroundings.