Mitigation of RFI in High-Resolution SAR Data – Algorithm Overview and Experimental Demonstration

Very high-resolution Synthetic Aperture Radar (SAR) imagery requires the transmitted signal to have a wide Radio Frequency (RF) bandwidth. This bandwidth often overlaps with other RF sources posing a source of unwanted RF Interference (RFI). SAR images affected by RFI typically suffer from severely degraded image quality as the interference signal masks the useful target signal. This paper presents an approach to detect and suppress narrowband RFI signals that can be applied either before or after SAR image formation. The detection is achieved by analyzing the signal energy in the range frequency domain. After detection, a non-linear combination of time domain least-mean-squares and frequency domain notch filtering is used to suppress the RFI. Real SAR data from the ICEYE satellite constellation is used to demonstrate the effectiveness of the proposed RFI mitigation strategy.