GB-SAR 시스템의 영상화 및 간섭기법 이훈열, 조성준, 성낙훈 강원대학교 지구물리학과 한국지질자원연구원 지반안전연구부 한국지구물리물리탐사학회 2007 학술대회 6 월 7-8 일 한국지질자원연구원

Contents Introduction Introduction GB-SAR System GB-SAR System SAR Focusing and Interferometry SAR Focusing and Interferometry Applications Applications Conclusion Conclusion

Introduction GB-SAR: Ground-Based Synthetic Aperture Radar GB-SAR: Ground-Based Synthetic Aperture Radar Synthetic Aperture Radar Synthetic Aperture Radar Imaging Radar Imaging Radar Azimuth aperture synthesis Azimuth aperture synthesis Ground-Based Ground-Based Fairly versatile system configuration Fairly versatile system configuration Multiple frequency (L, C, X, Ku, Ka, etc) Multiple frequency (L, C, X, Ku, Ka, etc) Full Polarization (VV, VH, HV, HH) Full Polarization (VV, VH, HV, HH) Ultimate SAR focusing Ultimate SAR focusing Zero Doppler centroid (stationary vehicle during Tx/Rx) Zero Doppler centroid (stationary vehicle during Tx/Rx) Accurate estimation of Doppler rate from geometry Accurate estimation of Doppler rate from geometry Topography Mapping: Cross-Track InSAR or Delta-K InSAR Topography Mapping: Cross-Track InSAR or Delta-K InSAR Surface Motion: Zero-baseline and short atmospheric path for Temporal Coherency, DInSAR and PSInSAR Surface Motion: Zero-baseline and short atmospheric path for Temporal Coherency, DInSAR and PSInSAR Useful for new SAR concept design Useful for new SAR concept design Previous Works Previous Works LISA (EU) for Avalanche and landslide monitoring LISA (EU) for Avalanche and landslide monitoring Other laboratory or field tests (UK, Japan) Other laboratory or field tests (UK, Japan)

GB-SAR System

System Configuration

SAR Focusing Algorithms AlgorithmsAdvantangeDisadvantageUsage Range-Doppler or ω-k Widely used for SAR Memory inefficiency for partial-focusing Near Range (full-focusing) Deramp-FFT Efficient in memory and CPU time Distortion in near range Far Range (partial-focusing) Time Domain Exact everywhere Time consuming Everywhere

DF vs RD (Indoor) (a) DF algorithm (b) RD algorithm

DF vs RD (outdoor) (a) DF algorithm (2MB Memory) (b) DF algorithm (geocoded)(b) RD algorithm (128MB Memory)

GB-SAR Resolutions (a) Full Focusing(b) Partial Focusing Range resolution:

GB-InSAR Configuration DInSAR DInSAR Cross-Track InSAR Cross-Track InSAR Delta-K InSAR Delta-K InSAR Cross-Track and Delta-K InSAR Cross-Track and Delta-K InSAR DInSAR with range change Cross-Track InSAR

GB-SAR Interferometry Change Phase Difference Range phase ramp Sensitivity DInSARRangenone Range Range Cross- Track InSAR Vertical baseline Height Height Delta-K InSAR Frequency shift Height Height Cross- Track and Delta-K InSAR and Height Height

KIGAM Roof-Top Test T1 T1 Range: Center frequency=5.3GHz Bandwidth=200MHz Sample=1601 Power=33dBm (2W) Azimuth: Scan length=5m Step=5cm Sample=101 T2: Temporal baseline of 20minutes (DInSAR) T2: Temporal baseline of 20minutes (DInSAR) T3: Spatial baseline of -30cm vertical (InSAR DEM) T3: Spatial baseline of -30cm vertical (InSAR DEM) T4: Frequency shift of -10MHz (Delta- K InSAR) T4: Frequency shift of -10MHz (Delta- K InSAR)

Image Area

VV T1

VH

HH

DInSAR (T2-T1) VV

Cross-Track InSAR (T3-T2) VV

Delta-K InSAR (T4-T3) VV

Cross-Track and Delta-K InSAR (T4-T2) VV

Automatic Acquisition with 2cm Step, :22pm- 4:20am, A1~A9 HH VV

Phase Errors Ideal Case A6-A5, HH Azimuth scan shift of 2cm. A9-A1, HH Range System Shift of 2mm

PSInSAR – Temporal Coherence TC of 9 acquisitions for 2 hours. Color scheme: black(0) to white(0.9) and blue (0.9) to red(1)

Conclusion We made a SAR system. We made a SAR system. A GB-SAR system was developed, tested, and waiting for applications. A GB-SAR system was developed, tested, and waiting for applications. Optimal GB-SAR focusing algorithms were tested. Optimal GB-SAR focusing algorithms were tested. Cross-Track and Delta-K InSAR were tested. Cross-Track and Delta-K InSAR were tested. DInSAR or PSInSAR were tested: Phase stability of 1° (0.1mm range) was achieved for several hours for stable reflectors, rendering phase change of 10 ° meaningful (1mm range accuracy for DInSAR). DInSAR or PSInSAR were tested: Phase stability of 1° (0.1mm range) was achieved for several hours for stable reflectors, rendering phase change of 10 ° meaningful (1mm range accuracy for DInSAR). GB-SAR can be used for various applications such as: GB-SAR can be used for various applications such as: Safety monitoring of natural or anthropogenic structures Safety monitoring of natural or anthropogenic structures Microwave backscattering properties of target Microwave backscattering properties of target New SAR system concept design New SAR system concept design More robust GB-SAR system optimized to a specific application will be developed. More robust GB-SAR system optimized to a specific application will be developed.

Thank You