Holographic SAR Volumetric Imaging Strategy for 3-D Imaging With Single-Pass Circular InSAR Data
Hanqing Zhang, Yun Lin, Fei Teng, Shanshan Feng, Wen Hong
Abstract
In this article, we present a novel synthetic aperture radar (SAR) 3-D imaging strategy using circular Interferometric SAR (InSAR) data. Our approach improves upon the Holographic SAR tomography (HoloSAR) techniques by eliminating the need for multi-baseline data collection nor residual motion error correction over a long curvilinear aperture. This may provide a simple yet effective 3-D imaging solution for perturbed airborne radar platforms. The key innovation is the first utilization of multi-aspect SAR interferograms to invert the 3-D or 4-D (3-D spatial coordinates (x, y, z) and radar azimuth angles θ) scattering power distribution of the imaged scene. Our fundamental assumption is that the imaged scene conforms approximately to a random volume scattering model. Thus, we can use the projection-slice theorem to establish a mathematical relationship between the multi-look interferograms and the scene’s 3-D/4-D scattering power distribution. The fundamental concepts and resolution theory of this new 3-D inversion strategy are developed in 3-D K-space using Fourier aperture synthesis theories. Then, we designed two algorithms for reconstructing a 3-D image: a filtered back-projection algorithm for reconstructing isotropic targets, and a compressed sensing imaging method for reconstructing large-scale targets with anisotropic behaviors. Finally, we verified the feasibility of proposed methods through experiments in real airborne scenarios.