Efficient time-varying interference suppression method for synthetic aperture radar imaging based on time-frequency reconstruction and mask technique

Owing to the vulnerability of synthetic aperture radar (SAR) system to interferences, effective interference suppression has been an urgent task for SAR imaging. In this work, a novel time-varying narrowband interference and wideband interference suppression method is presented based on time-frequency reconstruction and mask technique. This method consists of four key stages. First, the authors present an efficient signal reconstruction method (ESRM) based on eigenvalue decomposition from the Wigner distribution. Next, echoes contaminated by the interference are identified in the frequency domain and the jamming components are obtained by using the mask technique in time-frequency plane. Then, the ESRM is applied to quickly and accurately synthesise interference signals by incorporating the principle of energy minimum without the need of the prior knowledge of the interference. Finally, the interference components are subtracted from the echoes in data domain, and the well-focused SAR image is obtained by conventional imaging algorithm. Results of simulated and measured data prove the validity of the proposed method.