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ISRS2009, Haeundae Grand Hotel, Busan, Korea, 28-30 October, 2009. Development of F ocusing Algorithms for Arc-scanning Ground-Based Synthetic Aperture Radar. Hoonyol Lee Dept. of Geophysics, Kangwon National University Seong-Jun Cho and Kwang-Eun Kim
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ISRS2009, Haeundae Grand Hotel, Busan, Korea, 28-30 October, 2009 Development of Focusing Algorithms for Arc-scanning Ground-Based Synthetic Aperture Radar Hoonyol Lee Dept. of Geophysics, Kangwon National University Seong-Jun Cho and Kwang-Eun Kim Korea Institute of Geosciences and Mineral Resources
Contents • Introduction to ArcSAR • Focusing Algorithms for ArcSAR Spot and Scan Modes • Comparison of Resolutions • ArcSAR Spot Mode, ArcSAR Scan Mode, Linear-scanning GBSAR, and a conventional radar (ArcRAR) • Results • Conclusions
GB-SAR(KIGAM-KNU) • DInSAR tested: Phase stability of 1° (0.1mm range) was achieved for several hours for stable reflectors, rendering phase change of 10 ° to be assured (1mm accuracy). • PSInSAR displacement measurement: R2=0.9999 achieved. • GB-SAR can be used for various applications such as: • Safety monitoring of natural or anthropogenic structures • Microwave backscattering properties of target • New SAR system concept design
ArcSAR Concept AWS AWS
ArcSAR Geometry • Polar Imaging Domain: • Range and • “True” azimuth
Spot Mode Dual rotational motion (boom and antenna) Coherent Integration Arc can be 180 degree maximum. High resolution Limited azimuth coverage Scan Mode Single rotational motion (boom only) Coherent Integration Arc is the width of the antenna beam. Low resolution Full azimuth coverage ArcSAR Imaging Modes
Spot Mode Deramp-FFT Algorithm in Polar Format Range Compressed Signal: Coherent Integration Arc: Range Function: Scan Mode Range-Doppler Algorithm in Polar Format Range Compressed signal: Coherent Integration Arc: Range Function: ArcSAR Focusing
Spot Mode Taylor’s Expansion at : Deramp Function: Azimuth Compression: IFFT Scan Mode Taylor’s Expansion at : Matched Filter: Azimuth Compression: Matched Filtering ArcSAR Focusing
Spot Mode Focused Image: Azimuth (angular) Resolution: Phase: Scan Mode Focused Image: Azimuth (angular) Resolution: Phase: ArcSAR Focusing
Flowchart Raw Data Range Hamming Filter Range Compression Azimuth FFT Range Migration Range Migration Multiply Deramp function Azimuth Matched Filter Azimuth Hamming Filter Azimuth Hamming Filter Azimuth FFT Azimuth iFFT Geometric Correction Geometric Correction Output Output Deramp-FFT Range-Doppler
Further Research • A brand-new truck has arrived and is under reform. • Second motor control for ArcSAR Spot Mode will be added. • Integrated Controller • SAR, InSAR, Surface motion detector software • GPS, AWS • Increase Mileage!
Conclusions • Image focusing algorithms for ArcSAR were developed in polar coordinates. • The Deramp-FFT algorithm was used for ArcSAR Spot Mode and the Range-Doppler algorithm for ArcSAR Scan Mode. • Comparisons of image resolutions between various ground-based radar systems confirmed the advantages of ArcSAR: ArcSAR Spot Mode > Linear-scanning GBSAR > ArcSAR Spot Mode > ArcRAR 167.2 53.4 11.0 1 • The system will be mounted on a “new” truck and will provide a rapid response tool for various applications such as regional mapping and environmental hazard monitoring.