Transcript Development of Focusing Algorithms for Arc

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
Introduction to ArcSAR
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 RF Configuration
ArcSAR Design
Circular Rail and Extendable Boom
ArcSAR Truck
ArcSAR Leveler
ArcSAR Leveler
ArcSAR Data Acquisition
GB-SAR vs ArcSAR
GB-SAR
ArcSAR(World first)
Scan Type
Linear
Arc
Polarization
Full
Full
Scan Load
Heavy
Light
Azimuth Resolution
High
3 times Higher than
GB-SAR
Installation
Ground-fixed
Automobile: higher
mobility
Motion Control
Simple (linear motion)
Complex (2 rotational
motions)
SAR focusing
Conventional
New
Major application
DInSAR change
detection
Emergency Mapping
DInSAR change
detection
ArcSAR Focusing Algorithms
ArcSAR Geometry
Polar Imaging Domain:

Range
and

“True” azimuth
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
ArcSAR Focusing
Spot Mode
 Deramp-FFT Algorithm in Polar
Format
 Range Compressed Signal:
Scan Mode
 Range-Doppler Algorithm in
Polar Format
 Range Compressed signal:

Coherent Integration Arc:

Coherent Integration Arc:

Range Function:

Range Function:
ArcSAR Focusing
Spot Mode
 Taylor’s Expansion at
:
Scan Mode
 Taylor’s Expansion at

Deramp Function:


Azimuth Compression: IFFT

:
Matched Filter:
Azimuth Compression: Matched
Filtering
ArcSAR Focusing
Spot Mode
 Focused Image:
Scan Mode
 Focused Image:

Azimuth (angular) Resolution:

Azimuth (angular) Resolution:

Phase:

Phase:
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
Azimuth Resolutions
Results
Simulation: ArcSAR Spot Mode
Simulation: ArcSAR Scan Mode
ArcSAR Scan Mode Experiment
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
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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.