RFI Detection for Multichannel HRWS SAR System Based on Spatial Cross Correlation

Multichannel high-resolution and wide-swath (HRWS) imaging is an advanced digital beamforming technique for future synthetic aperture radar (SAR) systems. However, radio frequency interference (RFI) is a critical concern for HRWS SAR missions, which distorts measurements and produces image artifacts. In this paper, the spatial cross-correlation coefficients of multichannel HRWS SAR signals are investigated for RFI detection. It is found when the two channels are correlated, RFI-polluted areas present lower coherence values than non-polluted areas in the same scenarios, which makes previous methods fail. Further, this paper studies the case of two fully decorrelated channels to maximize the coherence difference among RFI and target echoes, and RFI detection is realized by exploiting the anomaly value of coherence. Experimental results of real airborne multichannel SAR data demonstrate that the RFI can be detected successfully.