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4_IGARSS11_HRWS.ppt
1. Performance Investigation on the High-Resolution Wide-Swath SAR System Operating in Stripmap Quad-Pol and Ultra-Wide ScanSAR Mode DLR - Institut für Hochfrequenztechnik und Radarsysteme F. Bordoni , M. Younis, G. Krieger IGARSS 2011, 24-29 July, Vancouver, Canada
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3. Displaced Phase Center Antenna >> high spatial resolution Multichannel Antenna Wide transmit pattern >> wide swath R(t) nadir H orb SCORE algorithm >> high gain HRWS (High-Resolution Wide-Swath) SAR System The HRWS SAR system is conceived to overcome the conventional trade-off between resolution and swath width Current SAR: 1 m v.s. 10 km; 16 m v.s. 100 km HRWS: 1 m v.s. 70 km (stripmap single-pol) Digital Beamforming
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6. Stripmap Quad-Pol: Timing Diagram Transmit alternately vertical & horizontal linear polarized pulses Double PRF (Pulse Repetition Frequency) Single-pol Quad-pol Timing Diagram Spatial resolution: 1 m x 1 m Nr. Subswaths: 12 Swath width smaller: 20 - 50 km Spatial resolution: 1 m x 1 m Nr. Subswaths: 6 Subswath width: 70 - 80 km PRF: 1650 – 1780 Hz PRF double: 3400 – 3800 Hz
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11. Swath width of 375 km complete imaging of the Earth with a repeat time of 8 days Ultra-Wide ScanSAR 375 km Imaging of the complete acces range (375 km) in a single pass 6 bursts // 6 subswaths Swath width: 375 km Spatial resolution: 1m x ?m
12. - - - Rx Patt. ___ Tx Patt. ___ 2-way Patt. Pattern Design & Performance Azimuth pattern shape key influence on ScanSAR performance The Phase Spoiling technique is used to obtain the Tx pattern
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Editor's Notes
- Let’s take a briefly look on the outline of the presentation. In the first part of the presentation it will be presented the actual context and the limitation that has motivated the study of a new approach based on the Adaptive Digital beam-Forming. Later on the different tools to better understand this approach are presented and finally the numerical results
In the actual context the remote sensing applications are demaning products with high resolution capabilities simulatenously with wide coverage. However, these are contardictory requirements. Inorder to overcome this limitation of the conventional SAR. It has been proposed a new technique that combines samrt antennas with multiple tx/rx antennas with digital signal processing. One of this approaches is the so called High Resolution Wide Swath combine with a digital beamforming technique SCORE. In this case the wider swath is obtained with a smaller tx antenna and a larger rx antenna compensate the reduced gain. The classical conflict between high resolution and wide swath is overcome using a multiple rx antenna in azimuth. The radiometric resolution is improved through a larger multi-channel antenna in elevation where a digital beam.forming technique SCORE allows to combine the signals and generate a sharp beam following the echo on the ground (with the maximum gain). The steering direction of SCORE corresponds to the acutal direction of arrival which is assumed to be a priori known, which is unique associated to the slant range or two-way time delay under the asumption of a spheical earth with no topography.
- Let’s take a briefly look on the outline of the presentation. In the first part of the presentation it will be presented the actual context and the limitation that has motivated the study of a new approach based on the Adaptive Digital beam-Forming. Later on the different tools to better understand this approach are presented and finally the numerical results
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