Detection and Geolocation of <i>P</i>-Band Radio Frequency Interference Using EcoSAR

Bollian, Tobias; Osmanoǧlu, Batuhan; Rincon, Rafael; Lee, Seung-Kuk; Fatoyinbo, Temilola

doi:10.1109/jstars.2018.2830745

Cited by 17 publications

(4 citation statements)

References 11 publications

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“…Rosenberg et al proposed constrained fast-time space time adaptive processing (STAP) techniques which exploit adaptive beamforming to suppress the interference with minimal distortion to the final image [64][65][66]. Bollian et al proposed using digital beamforming techniques for the 32-channel EcoSAR system [67][68][69].…”

Section: Spatial Filteringmentioning

confidence: 99%

Mitigation of Radio Frequency Interference in Synthetic Aperture Radar Data: Current Status and Future Trends

et al. 2019

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Radio frequency interference (RFI) is a major issue in accurate remote sensing by a synthetic aperture radar (SAR) system, which poses a great hindrance to raw data collection, image formation, and subsequent interpretation process. This paper provides a comprehensive study of the RFI mitigation techniques applicable for an SAR system. From the view of spectrum allocation, possible terrestrial and spaceborne RFI sources to SAR system and their geometry are analyzed. Typical signal models for various RFI types are provided, together with many illustrative examples from real measured data. Then, advanced signal processing techniques for removing RFI are reviewed. Advantages and drawbacks of each approach are discussed in terms of their applicability. Discussion on the future trends are provided from the perspective of cognitive, integrated, and adaptive. This review serves as a reference for future work on the implementation of the most suitable RFI mitigation scheme for an air-borne or space-borne SAR system.

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Section: Spatial Filteringmentioning

confidence: 99%

Mitigation of Radio Frequency Interference in Synthetic Aperture Radar Data: Current Status and Future Trends

et al. 2019

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“…In the processed bandwidth only three peaks can be made out in the HH and five peaks in the VH image. Note that AoA estimations on the EcoSAR data can be found in Reference [57]. The dual-track mode of EcoSAR doubles the covered swath, though this makes it necessary to reserve notches for ambiguity suppression to suppress signals from the opposite side.…”

Section: Resultsmentioning

confidence: 99%

Adaptive Antenna Pattern Notching of Interference in Synthetic Aperture Radar Data Using Digital Beamforming

et al. 2019

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Radio Frequency Interference (RFI) is a growing problem in Synthetic Aperture Radar (SAR) systems as scientific motivations push the radars to lower frequencies and as more wireless services share the frequency spectrum. New, advanced SAR instruments, such as NASA’s EcoSAR, DBSAR and DLR’s Tandem-L mission, employ a multichannel architecture capable of Digital Beamforming (DBF). Radars with DBF are capable of notching the antenna pattern in specific directions, which can be utilized to suppress RFI on board or in post-processing. A well-researched beamformer for this purpose is the Minimum Variance Distortionless Response (MVDR) Beamformer. However, the number of interferers that can be removed through notching is limited by the number of receive channels. It is therefore essential to adaptively change the antenna pattern notching throughout the image in time and frequency for the best results with a given number of receive channels. In this paper, we present several methods to achieve this notching by making use of the spatial SAR signal distribution in range time, range frequency, azimuth time and azimuth Doppler that is inherent to the SAR imaging geometry. Because this distribution is time-variable and yet predictable, it can be used to improve the angle of arrival estimation of the RFI and the adaptive notching. The presented methods can be applied to a Digital Beamforming (DBF) SAR signal with multiple channels in elevation and/or in azimuth. Simulations show that the proposed methods increase the ability to notch out-of-swath interference from multiple directions and lessen the impact on in-swath interference. The improvement of the interferometric coherence for a single-pass interferogram acquired by NASA’s EcoSAR system (capable of DBF in elevation) is demonstrated. The removal of periodic RFI artifacts is achieved.

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“…The influence of the angular resolution on the estimation gap length is then calculated by inserting ∆θ DBF into Eq. (11). The sweeping velocity is computed via [45]:…”

Section: A the Impact Of The Spatial Resolutionmentioning

confidence: 99%

“…In addition, a study by MacDonald Dettwiler Associates found an average backscatter increase of 3 dB from 1996 to 2012 over Ottawa, Canada, likely caused by RFI [4]. Many other SAR systems have reported interferences across P-, L-, and C-band [6], [7], [8], [9], [10], [11]. This trend is expected to continue [12], [13] because frequency bands assigned to spaceborne SAR are shared with other services [14].…”

Section: Introductionmentioning

confidence: 99%

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

Bollian

Younis

Krieger

et al. 2022

IEEE Trans. Geosci. Remote Sensing

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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.

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Detection and Geolocation of P-Band Radio Frequency Interference Using EcoSAR

Cited by 17 publications

References 11 publications

Mitigation of Radio Frequency Interference in Synthetic Aperture Radar Data: Current Status and Future Trends

Mitigation of Radio Frequency Interference in Synthetic Aperture Radar Data: Current Status and Future Trends

Adaptive Antenna Pattern Notching of Interference in Synthetic Aperture Radar Data Using Digital Beamforming

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

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