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Solutions for high-resolution wide-swath SAR imaging. Left: multiple beam SAR. Middle left: displaced phase center antenna technique. Middle: quad-element rectangular array SAR. Middle right: highresolution wide-swath (HRWS) SAR. Right: High resolution wide swath SAR employing a reflector antenna in combination with a digital feed array.
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This paper reviews advanced multi-channel SAR system concepts for the imaging of wide swaths with high resolution. Several novel system architectures employing both direct radiating arrays and reflector antennas fed by a digital array are introduced and compared to each other with regard to their imaging performance. In addition, innovative SAR ima...
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... proposals resolve the azimuth resolution vs. wide swath coverage dilemma by combining a multi-channel radar receiver with a small aperture transmitter illuminat- ing a wide area on the ground. Examples are the squinted multiple beam SAR (Figure 2, left, [2]), the displaced phase centre antenna (DPCA) technique ( Figure 2, sec- ond column, [3]), the Quad Array SAR system ( Figure 2, third column, [4]), and the High-Resolution Wide-Swath (HRWS) SAR system ( Figure 2, fourth column, [5]). An interesting alternative to a direct radiating array is the combination of a reflector with a digital feed array as suggested in [6] [7] [8]. ...
Context 2
... proposals resolve the azimuth resolution vs. wide swath coverage dilemma by combining a multi-channel radar receiver with a small aperture transmitter illuminat- ing a wide area on the ground. Examples are the squinted multiple beam SAR (Figure 2, left, [2]), the displaced phase centre antenna (DPCA) technique ( Figure 2, sec- ond column, [3]), the Quad Array SAR system ( Figure 2, third column, [4]), and the High-Resolution Wide-Swath (HRWS) SAR system ( Figure 2, fourth column, [5]). An interesting alternative to a direct radiating array is the combination of a reflector with a digital feed array as suggested in [6] [7] [8]. ...
Context 3
... proposals resolve the azimuth resolution vs. wide swath coverage dilemma by combining a multi-channel radar receiver with a small aperture transmitter illuminat- ing a wide area on the ground. Examples are the squinted multiple beam SAR (Figure 2, left, [2]), the displaced phase centre antenna (DPCA) technique ( Figure 2, sec- ond column, [3]), the Quad Array SAR system ( Figure 2, third column, [4]), and the High-Resolution Wide-Swath (HRWS) SAR system ( Figure 2, fourth column, [5]). An interesting alternative to a direct radiating array is the combination of a reflector with a digital feed array as suggested in [6] [7] [8]. ...
Context 4
... proposals resolve the azimuth resolution vs. wide swath coverage dilemma by combining a multi-channel radar receiver with a small aperture transmitter illuminat- ing a wide area on the ground. Examples are the squinted multiple beam SAR (Figure 2, left, [2]), the displaced phase centre antenna (DPCA) technique ( Figure 2, sec- ond column, [3]), the Quad Array SAR system ( Figure 2, third column, [4]), and the High-Resolution Wide-Swath (HRWS) SAR system ( Figure 2, fourth column, [5]). An interesting alternative to a direct radiating array is the combination of a reflector with a digital feed array as suggested in [6] [7] [8]. ...
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... To ensure the precision of mechanical beamsteering approach, the mass of antenna should not be too big to cause reaction on the platform itself. Thus, reflector antenna is especially suitable for our approach [19], [20]. ...
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... By this the receive beam is scanned across the swath from near to far range. This scanning operation, in the SAR literature denoted as SCORE (SCan-On-REceive)[21],[22]can be efficiently implemented by means of digital feed array hardware[24]. Such a concept is presented on the right side ofFigure 9. ...
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with advanced digital beamforming techniques.
... This SCORE principle has been extended to analog reflector SAR systems by [15], dedicated to the improvement of the performances of SAR systems in terms of 'edge losses' and 'range ambiguities'. In the frame of ultra-wide-swath imaging a reflector SAR system employing a digital feed array is presented for the first time in [4] and further investigated in [7], [16]. The SCORE operation principle of reflector-based SAR systems with linear digital feed arrays is sketched in Fig. 1. ...
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... [8] to address azimuth resolution limits. The use of multiple receivers introduces new degrees of freedom in system design parameters that allow higher performance [8]. ...
... to address azimuth resolution limits. The use of multiple receivers introduces new degrees of freedom in system design parameters that allow higher performance [8]. Moreover, by including multiple receiving channels, multibaseline interferometry can be easily addressed by exploiting same time multiangular imaging of the target area. ...
Successful state-of-the-art space synthetic aperture radar (SAR) systems-based in active electronic steerable antenna (AESA) have reached a high degree of operation flexibility and achieved performance. Nevertheless, the possibility to provide wide-swath images with high resolution is still a challenge requiring the application of new concepts and system architectures. Multiple channel-based SAR systems have become the perfect trend to follow in next generation SAR programs, as they will allow to overcome the resolution/coverage tradeoff by enabling the application of digital beamforming (DBF) or multiple input multiple output (MIMO) techniques. This paper presents a multichannel reconfigurable SAR system prototype concept being developed as demonstrator for next generation SAR operation and applications, enabling the use of DBF on receive or MIMO-SAR. System architecture and key subsystems are described, with emphasis in reconfigurable capabilities and internal calibration. Example performance results for practical application of presented architecture are also provided.
... Therefore, by substituting (19) into the inequality (17) we can obtain that for sufficient separation of the blind ranges, it should be satisfied that ...
A promising candidate for ultra-wide-swath spaceborne synthetic aperture radar (SAR) imaging with a fine resolution is the multiple-elevation-beam (MEB) SAR. Conventional MEB SAR suffers from deterioration of noise-equivalent sigma zero (NESZ) and range ambiguity-to-signal ratio (RASR) performances in the far end of the imaging swath and disturbances between different subbeam elevations. Another inherent problem of previously proposed MEB SAR systems is the blind range effect, which blocks continuous mapping. In this paper, we introduce a potential modified MEB SAR system based on space-time-frequency waveform encoding on transmit and on digital beamforming (DBF) on receive that provides a much improved performance of NESZ and RASR, a lower requirement for the transmit peak power, and a more flexible signal energy distribution. Furthermore, to overcome the blind range problem, a periodic sweep of pulse repetition interval (PRI) design strategy is employed. In this paper we are developing the idea of sweep-PRI mode into a complete detailed processing scheme. The explicit signal model, the instructive system design guideline, and the corresponding signal processing scheme for this operational mode are described in detail. A recurrent nonuniform reconstruction algorithm is adopted first to cope with the problems of nonuniform sampling and periodic gaps in the azimuth preprocessing. Additionally, an in-depth analysis of system performance for the presented MEB SAR system is carried out. Finally, an example system with a 400-km-wide swath and 3-m resolution is designed based on the proposed strategies. The simulation results demonstrate that the presented SAR system shows satisfactory performance.
... to a considerable improvement in system performance when compared to the state-of-the-art SAR, and its benefits can be maximized when combined with digital beamforming (DBF) capability [5]. So, SAR systems with DBF functionality on receive are spotlighted as a promising way toward the next generation of SAR instrument [6]- [10]. The high-resolution wide-swath (HRWS) SAR is a representative example of the DBF SAR concept. ...
... Jung-Hyo Kim (S'04-M' [10][11][12][13] ...
In this paper, we introduce a novel multiple–input multiple–output (MIMO) synthetic aperture radar (SAR) concept for multimodal operation. The proposed system employs waveforms based on the orthogonal frequency division multiplexing (OFDM) technique and digital beamforming (DBF) on receive. Thereby, it becomes feasible to maximize spatial degrees of freedom, which are necessary for the multimodal operation. The proposed MIMO SAR system produces multiple high-resolution wide-swath SAR imageries that are used for coherent postprocessing. Through this paper, we aim to open up a new perspective of using MIMO concept for a wide-swath SAR imaging with high resolution in interferometric and polarimetric modes, based on OFDM and DBF techniques. Therefore, this paper encompasses broad theoretical backgrounds and general system design issues as well as specific signal processing techniques and aspects.
