On-Ground RFI Mitigation for Spaceborne Multichannel SAR Systems Using Auxiliary Beams

Abstract

Radio Frequency Interference (RFI) is becoming a major concern for future Synthetic Aperture Radar (SAR) missions due to the increased user demand for frequency occupation in a number of applications. Each occurrence of interference introduces artifacts in the radar imagery, biasing the measurements and leading to erroneous results. In addition to conventional techniques, the use of multichannel SAR for RFI mitigation has been proposed because its Digital Beamforming (DBF) capability allows for a spatial filtering of the received signals. Thereby, it becomes possible to remove RFI that arrives from a different direction than the SAR signal.Past publications on the topic presented highly flexible spatial filtering techniques. Those methods require either additional on-board processing or a substantial increase of the downlink capacity. This paper shows that by slightly reducing the flexibility of the spatial filtering, DBF can be utilized for RFI mitigation without either drawbacks: the processing is performed onground after downlinking the data and the data volume remains manageable. This is achieved with auxiliary beams. Their concept and limitations are discussed in detail in this paper and are supported with simulated RFI mitigation results. Furthermore, it is shown that the information collected with an auxiliary beam can also be used to filter the RFI signal when it is spatially non-orthogonal to the SAR signal.

Joint Radio Frequency Interference and Deceptive Jamming Suppression Method for Single-Channel SAR via Subpulse Coding

“…In recent years, scholars have gradually paid attention to the harms caused by these interferences. Therefore, interference suppression technology for SAR is now becoming a hot research spot [6], [7], [8]. In terms of RFI suppression methods, they This work is licensed under a Creative Commons Attribution 4.0 License.…”