Holographic SAR Volumetric Imaging Strategy for 3-D Imaging With Single-Pass Circular InSAR Data

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 multibaseline 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 multiaspect SAR interferograms to invert the 3-D or 4-D (3-D spatial coordinates
$(x,y,z)$
and radar azimuth angles
$\theta $
) 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 (PST) to establish a mathematical relationship between the multilook 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 (FBP) 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.