DBFSAR: An airborne very high-resolution digital beamforming SAR system

Reigber, Andreas; Nottensteiner, Anton; Limbach, Markus; Jäger, Marc; Kosc, Alicja; Scheiber, Rolf; Fischer, Jens; Maria, A. Di; Müller, G.; Que, Russel; Künemund, Maren; Trappschuh, K.; Pasch, Sebastian; Geswein, D.; Hoflmayr, D.; Gabler, Bernd; Keller, Martin; Horn, Ralf; Moreira, Alberto

doi:10.23919/eurad.2017.8249175

Cited by 8 publications

(8 citation statements)

References 4 publications

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“…Therefore, to achieve high resolution in the azimuth direction and wide-range swaths in the range direction spontaneously, lower transmission pulse repetition frequency (PRF) and multiple channels for echo receiving are required to resolve the contradiction between the two. This model demonstrates the formation of a multiphase center in the azimuth direction [2], which has been verified by the novel multifrequency polarized airborne SAR [3] of the German Aerospace Center (DLR) and Canadian second commercial Earth observation SAR satellite [4]; its major problems are channel calibration and azimuth signal reconstruction.…”

Section: Introductionmentioning

confidence: 73%

“…The DBF development project was initiated by the German DLR in 2014. Based on this multiple-receiving-channel model, the project uses transmission beams with large elevation angles for illumination and narrow receiving beams to scan and track the pulse echoes on the ground -also referred to as the ScanSAR imaging mechanism -which enables SAR imaging with a meter-level resolution in a 200-250-km band [5]. The DBF system can control the pointing direction of multiple antenna subbeams at the receiving end through phase weighting, thereby integrating clutter suppression, beam scanning, and high-gain narrow-beam accurate imaging, which solves the traditional phased-array radar's disadvantages of not being able to control beam direction because of fixed channel size.…”

Section: Introductionmentioning

confidence: 99%

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Digital Beamforming in Elevation for Moving Surface Ships

Zhang¹,

Jiang²

2019

PIER C

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Moving target ship imaging in large sea area has always been the focus of military and civilian attention. Due to the limitation of pulse repetition frequency (PRF), there is a contradiction between wide mapping band and azimuth accuracy. The nonlinearity of PRF can also cause discontinuity of mapping band. Therefore, this paper proposes a method of digital beamforming-scan on receiving (DBF-SCORE) beam scanning based on airborne phased array radar to achieve the requirement of scene mapping band with lower PRF. The adaptive Capon spectrum estimation is used to dynamically adjust the beam pointing so that it can always point to the moving target for accurate imaging. Considering the nonuniform sampling of the transmitting pulse period of the antenna, the azimuth nonuniform Fourier transform (NUDFT) algorithm is used to re-sample the nonuniform periodic signal of the multi-channel receiving antenna and obtain the uniform spectrum signal. Finally, fine focusing of moving target is achieved by local phase gradient algorithm (PGA) algorithm, and accurate imaging of moving target in large sea area is realized. The validity of the algorithm can be verified by simulation and real data imaging, which can be used for reference in phased array SAR imaging of moving targets.

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Section: Introductionmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Digital Beamforming in Elevation for Moving Surface Ships

Zhang¹,

Jiang²

2019

PIER C

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“…Indeed, this processing time factor is data dependent and therefore further work is needed considering other data sets with different number of roads and moving vehicles. This evaluation is foreseen for the next experiments with the novel DLR's DBFSAR system (Reigber et al, 2017), which had its maiden flight in November 2016. Anyhow, this result acknowledges the great potential of the proposed processor towards real-time traffic monitoring.…”

Section: Controlled Vehiclesmentioning

confidence: 99%

Fast post-Doppler STAP with road map for traffic monitoring: overview and first results

2019

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Abstract. Synthetic aperture radar (SAR) is an efficient solution for road traffic monitoring due to its high spatial resolution and independence from daylight and weather conditions. In this sense, a number of ground moving target indication (GMTI) algorithms have been developed, whereas their robustness is often achieved with high costs, increased hardware complexity and high computational burden. This paper presents a fast GMTI processor that blends the powerful post-Doppler space-time adaptive processing (PD STAP) with an a priori known road map and digital elevation model (DEM). The algorithm presents great potential for real-time processing, decreased hardware complexity and low costs compared to state-of-the-art systems. It is tested using real 4-channel X-band radar data acquired with the DLR's airborne F-SAR.

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“…One of these promising uses is in the field of remote-sensing, where Synthetic Aperture Radar (SAR) has become an important application. Airborne SAR sensors provide a key scope of research in order to test and experiment new systems and to support future space missions [1].…”

Section: Introductionmentioning

confidence: 99%

High Permittivity CPW-SIW Power Divider for Antenna Feed Networks in Airborne Phased Arrays Applications

Lorente

Schreiber

Limbach

et al. 2021

2020 17th European Radar Conference (EuRAD)

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An extremely compact design of a power divider in Substrate Integrated Waveguide (SIW) and fed by means of a Coplanar Waveguide (CPW) line is presented in this paper. The proposed solution presents a relative low insertion loss and good adaptation (measurements show an S11 better than -20 dB for the centre frequency and below -15 dB for a 30% bandwidth) in X-band, despite the use of a substrate with a high dielectric permittivity (εr = 9.8). In order to validate the design, various topologies of the power divider are manufactured, measured and compared with the simulated data. These power splitters will be implemented in the feed network of a phased array for an airborne radar system with Digital Beamforming capabilities operated by the German Aerospace Center.

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DBFSAR: An airborne very high-resolution digital beamforming SAR system

Cited by 8 publications

References 4 publications

Digital Beamforming in Elevation for Moving Surface Ships

Digital Beamforming in Elevation for Moving Surface Ships

Fast post-Doppler STAP with road map for traffic monitoring: overview and first results

High Permittivity CPW-SIW Power Divider for Antenna Feed Networks in Airborne Phased Arrays Applications

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