Adaptive Sub-Aperture Integration for Wide-Angle Synthetic Aperture Radar

In this paper, we present an adaptive sub-aperture integration method for wide-angle synthetic aperture radar (SAR) for improved imaging, with emphasis on short-to-medium range applications. In order to avoid full-aperture integration, traditional approaches use fixed-width sub-apertures, which may not conform to the persistence angle of the scatterers. Coherent integration gains over the aperture are possible if integration is carried out over the persistence angle of the scatterers, because integrating shorter than the persistence angle may spread the scattering response across multiple sub-apertures or, conversely, integrating more than the persistence angle may cause noise accumulation along with the useful signal. In this paper, we propose to use change-point detection methods to estimate the persistence widths of the scatterers, and consequently enhance the coherent integration gains, resulting in improved imaging. We compare our proposed methods with the standard integration approaches as well as a recently proposed adaptive integration approach. We provide qualitative and quantitative analyses to prove that our proposed methods outperform the existing approaches. We present experimental results on the real-data of our low-terahertz (THz) radar as well as a publicly available dataset to validate our claims.