1. 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 ISRS2009, Haeundae Grand Hotel, Busan, Korea, 28-30 October, 2009

2. 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

3. Introduction to ArcSAR

4. 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: R 2 =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

5. ArcSAR Concept AWS

6. ArcSAR RF Configuration

7. ArcSAR Design

8. Circular Rail and Extendable Boom

9. ArcSAR Truck

10. ArcSAR Leveler

12. ArcSAR Data Acquisition

13. GB-SAR vs ArcSAR GB-SARArcSAR(World first) Scan TypeLinearArc PolarizationFull Scan LoadHeavyLight Azimuth ResolutionHigh 3 times Higher than GB-SAR InstallationGround-fixed Automobile: higher mobility Motion ControlSimple (linear motion) Complex (2 rotational motions) SAR focusingConventionalNew Major application DInSAR change detection Emergency Mapping DInSAR change detection

14. ArcSAR Focusing Algorithms

15. ArcSAR Geometry Polar Imaging Domain:  Range and  “True” azimuth

16. ArcSAR Imaging Modes 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

17. ArcSAR Focusing 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:

18. 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

19. ArcSAR Focusing Spot Mode  Focused Image:  Azimuth (angular) Resolution:  Phase: Scan Mode  Focused Image:  Azimuth (angular) Resolution:  Phase:

20. Flowchart Raw Data Range Hamming Filter Range Compression Range Migration Azimuth FFT Multiply Deramp function Azimuth Hamming Filter Azimuth FFT Range Migration Azimuth Matched Filter Azimuth Hamming Filter Azimuth iFFT Geometric Correction Output Geometric Correction Output Deramp-FFTRange-Doppler

21. Azimuth Resolutions

22. Results

23. Simulation: ArcSAR Spot Mode

24. Simulation: ArcSAR Scan Mode

25. ArcSAR Scan Mode Experiment

26. 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!

27. 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.