Download - 차량탑재형 ArcSAR 시스템 개념설계
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차량탑재형 ArcSAR 시스템 개념설계차량탑재형 ArcSAR 시스템 개념설계
2008. 3. 21. 2008. 3. 21. 대한원격탐사학회 춘계학술발표회 대한원격탐사학회 춘계학술발표회
1) 조성준 , 2) 이훈열 , 1) 김광은1) 한국지질자원연구원2) 강원대학교
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Agenda
• 연구배경 및 목적• Introduction of GB-SAR• Concept of ArcSAR• Hardware configuration of ArcSAR• Imaging geometry of ArcSAR• 향후 추진 계획
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연구배경 및 목적
• 레일형 GB-SAR 는 반복측정을 통해 mm 이내의 변형까지 감지할 수 있는 높은 분해능을 자랑
• 레일을 모니터링 위치에 고정시켜야 하는데 고정밀 레일의 제작비용이 매우 비싸며 , 측정장치의 운반과 설치 역시 매우 복잡
• 차량에 원형레일을 탑재하여 신속한 기동을 확보• 합성구경의 길이를 늘리며 영상영역을 확장한 Arc-
SAR 개발
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GB-SAR
• GB-SAR: Ground-Based Synthetic Aperture Radar– Synthetic Aperture Radar
• Imaging Radar• Azimuth aperture synthesis
– Ground-Based• Fairly versatile system configuration
– Multiple frequency (L, C, X, Ku, Ka, etc)– Full Polarization (VV, VH, HV, HH)
• Ultimate SAR focusing– Zero Doppler centroid (stationary vehicle during Tx/Rx)– Accurate estimation of Doppler rate from geometry
• Topography Mapping: Cross-Track InSAR or Delta-K InSAR• Surface Motion: Zero-baseline and short atmospheric path for
Temporal Coherency, DInSAR and PSInSAR• Useful for new SAR concept design
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SAR Focusing – Point Target
rang
e
azimuth
original After range compression
After migration After azimuth compression
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State of the art of GB-SAR
• LISA SAR (Italy)• GB-POLInSAR (Australia)• GB-SAR (Japan)• Mobile SAR (Korea)
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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 structuresMicrowave backscattering properties of targetNew SAR system concept design
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System Configuration
T X R X O U TINM o t io nC o n t ro l
GP IB
T x V - p o lT x H - p o l
R x H - p o lR x V - p o l
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GB-SAR System(KIGAM-KNU)
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SAR Focusing Algorithms
Algorithms Advantage Disadvantage Usage
Range-Doppler or ω-k
Widely used for SAR
Memory inefficiency for
partial-focusing
Near Range (full-focusing)
Deramp-FFTEfficient in
memory and CPU time
Distortion in near range
Far Range(partial-focusing)
Time DomainExact
everywhereTime
consumingEverywhere
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ArcSAR Concept design
AWSAWS
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GB-SAR vs ArcSAR
GB-SAR ArcSAR(World first)
Scan Type Linear Arc
Scan Load Heavy Light
RF stability Stable Stable
Resolution HighHigher due to wider azimuth bandwidth
Installation Ground-fixedAutomobile: higher mobility
Phase repeatability High Low (Still now)
SAR focusing Conventional New
Major applicationDInSAR change detection
Emergency Mapping(Still now)DInSAR change detection (future)
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ArcSAR Hardware configuration
T X R X O U TIN
M o t io nC o n tro l
GP IB
T x V - p o lT x H - p o l
R x H - p o lR x V - p o l
T X R X
Exp re ss
R S - 2 3 2
S y n ch ro n o u sT u rn ta b le
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VNA(Vector Network Analyzer)
Stepped frequencyBoth of Tx and RxFlexibility10 MHz – 20 GHz
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Antenna
H-Pol radiation pattern
Dual-
Polarimetric
Square Horn
Antenna
Frequency(GHz) 5.0~5.6 5.0~5.6
Beam WidthE-Plane(deg) 15(nominal) 12.1~13
H-Plane(deg) 15(nominal) 15.5~17.5
Gain(dBi) 20(nominal) 20.5 min.(20.5~21.8)
VSWR 1.5 max. 1.4 max.
Isolation 35dB 이하 50dB 이하
Weight(kg) 4 max. 3.1 max.
Input Impedance(Ω) 50 50
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Amp and RF switch
Operating Freq.: 2~6 GHzPower Gain: 34 dB Maximum input: 6 dBm
Operation Freq.: ~20GHzGPIB interface3 중 1X2 SPDT
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Acquisition software
Start
Initialize all system
Move to start position
Acquisition Call cal:VV:Switching:Call cal:VH:Switching:Call cal:HV:Switching:Call cal:HH:Switching
End
Move or Stop
Callibration
Save data
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Design of a arc-rail
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ArcSAR Standard Mode: 360˚ coverage with moderate resolution
ArcnIntegratioCoherent:
,Wavelength:
where
2:ResolutionAngular
s
s
L
λ
L
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ArcSAR Spot Mode: Limited coverage with higher resolution
ArcnIntegratioCoherent:
,Wavelength:
where
2:ResolutionAngular
s
s
L
λ
L
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향후 추진계획
• ArcSAR 레일 제작• 자료획득 프로그램 개발• ArcSAR 포커싱 알고리듬 개발• 획득 및 자료처리 프로그램 통합• 현장 테스트 (GB-SAR 와 비교실험 )• 위치보정 알고리듬 개발• 모니터링 테스트