Subtraction of radio frequency interference with digital beamforming in EcoSAR flight data

Wideband radar systems operating at L- or P-band encounter an increasing amount of Radio Frequency Interference (RFI). If this RFI is not removed from the obtained radar signal, the quality of extracted science data can be decreased significantly. The removal of RFI can be improved with Digital Beamforming (DBF), a technique that is becoming more important in many radar applications. DBF enables to digitally steer the antenna beam into different directions and to place nulls into the antenna pattern. This technology is implemented in EcoSAR, a synthetic aperture radar (SAR) operating at P-band. Further, in data acquired by EcoSAR in Costa Rica in 2014, the impact of multiple RFI sources can be observed. This gives the opportunity to implement and test new RFI mitigation techniques based on DBF. In this paper, we estimate RFI with DBF and subtract it from EcoSAR data. The method is applied to several acquisitions and results are being presented.