On-Board RFI Detection for Reflector-Based Multichannel SAR Systems

Abstract

Correcting for Radio Frequency Interference (RFI) has become a critical aspect of current and future Synthetic Aperture Radar (SAR) missions. While most RFI mitigation methods suffer significant drawbacks (e.g., loss of resolution) or require individual filter parameters for each acquisition, spatial filtering methods only rely on system design parameters, such as antenna size. Further, combining spatial filtering with digital beamforming (DBF) allows for the removal of in-swath interference while the instantaneous SAR and RFI signal arrive from different directions. One option to apply a DBF-based RFI mitigation on the ground in post processing are auxiliary beams. Hereby, the RFI is measured with simultaneous auxiliary beams and this information is downlinked at the cost of a small increase of data volume. This paper presents an on-board implementation of RFI detection, which can then be used to select the best auxiliary beams.