Heterogeneous RFI Mitigation in Image-Domain via Subimage Segmentation and Local Frequency Feature Analysis

Radio frequency interference (RFI) may degrade the quality of remote sensing images acquired by spaceborne synthetic aperture radar (SAR). In the interferometric wide-swath mode of the Sentinel-1 satellite, the SAR receiver may capture multiple types of RFI signals within a single observation period, which is referred to as heterogeneous RFI, increasing the complexity of interference detection and mitigation. This article proposes a heterogeneous interference mitigation method based on subimage segmentation and local spectral features analysis. The proposed method divides the original single look complex image into multiple subimages along the range direction, enhancing the representation of interference features in the range frequency domain. Spectral analysis is then performed on each subimage to detect and mitigate interference. Finally, the image after RFI mitigation is reconstructed by stitching the subimages together. Experiments were conducted using simulated interference data generated from LuTan-1 and measured interference data from Sentinel-1. The results demonstrate that the proposed method can effectively mitigate RFI artifacts in various typical interference scenarios and restore the obscured ground object information in the images.