Narrowband RFI Suppression on High-Resolution Wide-Swath SAR Systems via Low-Rank Recovery

Abstract

For a spaceborne or an airborne synthetic aperture radar (SAR) system, it may be easily interfered with radio frequency interferences (RFIs) due to the increase demand for frequency occupation. The RFIs introduce artifacts in the focused SAR imagery, resulting in high noise floor and erroneous interpretations. Previous works on narrowband RFI mitigation mainly focused on single-channel SAR systems, while with the development of SAR imaging technology, the high-resolution wide-swath (HRWS) imagery technology now reaches its maturity to finally take shape in current SAR systems. To obtain HRWS images, the multi-channel SAR (MC-SAR) system has been employed to tackle the contradictory requirements for both high resolution and low pulse repetition frequency (PRF). In this paper, we propose a novel interference-mitigation model and analyze the low-rank property of the narrowband RFI for HRWS SAR systems. Then, we employ an image-domain sparse regularization to protect the real echoes of the SAR system and mitigate the RFIs by solving the low-rank recovery problems of RFIs. The real airborne SAR data is used to demonstrate the effectiveness of the proposed method.