FR2.L09 - PROCESSING OF MEMPHIS MILLIMETER WAVE MULTI-BASELINE INSAR DATA

IGARSS’10

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Applying PSI and Tomographic Applying PSI and Tomographic techniques using Radarsat-2 techniques using Radarsat-2

Spotlight data: a caseSpotlight data: a casestudy for Edmonton areastudy for Edmonton area

Valentin PoncosValentin Poncos(1)(1), John Dehls, John Dehls(2)(2), , Gianfranco FornaroGianfranco Fornaro(3)(3), Diego , Diego RealeReale(3)(3)

(1)(1) University of Calgary, Alberta, Canada University of Calgary, Alberta, Canada(2)(2) Alberta Geological Survey, Edmonton, Canada Alberta Geological Survey, Edmonton, Canada

(3)(3) Institute for Electromagnetic Sensing of the Environment (IREA) Institute for Electromagnetic Sensing of the Environment (IREA) – National Research Council (CNR), Naples, Italy– National Research Council (CNR), Naples, Italy

Applying Tomographic techniques Applying Tomographic techniques using TerraSAR-X stripmap data: a using TerraSAR-X stripmap data: a

casecasestudy for Edmonton areastudy for Edmonton area

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Outline

• DESCRIPTION OF THE GEOLOGICAL LAYOUT

• ANALYSIS OF THE DEFORMATION RESULTS AT LOW RESOLUTION

• FULL RESOLUTION DEFORMATION RESULTS ANALISYS

• ANALYSIS ON THE SEPARATION OF SCATTERERS ON BUILDINGS

• CONCLUSIONS

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Geological hazards in AlbertaGeological hazards in Alberta

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Geological setting Geological setting

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LocationLocation

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Calgary

Edmonton

Edmonton’s River valley is inherently unstable due to the action of North Saskatchewan River and very weak clay layers.

Coal mining from 1870’s to 1970 lead to further destabilization.

River bank collapse and subsidence are significant hazards today.

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Landslides in EdmontonLandslides in Edmonton

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Coal mining in EdmontonCoal mining in Edmonton

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17 TerraSAR-X acquisitions over the city of Edmonton, Alberta (CANADA) (from 2008. 05. 10 to 2008. 11. 13)

Imaging Mode: Single Polarization Stripmap

Orbit Direction: AscendingBeam Identification: strip_014Orbit Number: 10551

Incidence Angle: 44°Look Direction: Right

Azimuth resolution: 3.3 metersSlant Range resolution: 1.8 meters

Polarisation: VV

THE TERRASAR-X DATA SET OVER EDMONTON THE TERRASAR-X DATA SET OVER EDMONTON

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TERRASAR-X STRIPMAP FRAMETERRASAR-X STRIPMAP FRAME

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Distribution of the AcquisitionsDistribution of the Acquisitions

• 17 Stripmap acquisition 17 Stripmap acquisition

from May to November, from May to November,

20092009

• Maximun baseline Maximun baseline excursion of about 380mexcursion of about 380m

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DATA ANALYSIS BLOCK DIAGRAM

ZERO BASELINE STEERING

DEM

INTERFEROGRAMSTACKING ANALYSIS

APD AND DEFORMATIONESTIMATION

ATMOSPHERIC ANDDEFORMATION

REMOVAL

TOMOGRAPHIC FULL RESOLUTION ANALYSIS

Registered SLC Stack

LOW RESOLUTION DEFORMATION

PRODUCT

SINGLE SCATTERERS PRODUCT

DOUBLE SCATTERERS PRODUCt

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Tomographic imaging: 3DTomographic imaging: 3D

By synthesizing an antenna also in the slant height direction orthogonal to the line of sight we are able to analyze the vertical structure of the scattering thus extending SAR imaging form 2D (azimuth-slant range) to 3D (azimuth-slant range-slant height)

Scatte

ring pro

file

los

Slan

t heig

ht

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4D SAR Imaging (Differential SAR 4D SAR Imaging (Differential SAR Tomography)Tomography)

r

s

N acquisitions with spatial baseline distribution and temporal distribution

Nbb ......1Ntt ......1

ground range

range eleva

tion

Sate

llite

pas

ses

F. Lombardini, “Differential Tomography: a New Framework for SAR Interferometry “, IEEE Trans. Geosci. Remote Sens., 43, pp. 37-44, 2005.G. Fornaro, D. Reale, F. Serafino, "Four-Dimensional SAR Imaging for Height Estimation and Monitoring of Single and Double Scatterers", IEEE Trans. Geosci. Remote Sens., Jan. 2009, vol. 47 (1), 224-237

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LOW RESOLUTION DEFORMATION RESULTSLOW RESOLUTION DEFORMATION RESULTS

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LOW RESOLUTION DEFORMATION RESULTSLOW RESOLUTION DEFORMATION RESULTS

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LOW RESOLUTION DEFORMATION RESULTSLOW RESOLUTION DEFORMATION RESULTS

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FULL RESOLUTION (TOMOGRAPHIC) RESULTS FULL RESOLUTION (TOMOGRAPHIC) RESULTS (Dominant scatterers) (Dominant scatterers)

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TOMOGRAPHIC RESULTS (Dominant Scatterer)TOMOGRAPHIC RESULTS (Dominant Scatterer)

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THE LAYOVER EFFECT OVER BUILDINGS

ROOFFACADEGROUND

FACADEGROUND

IGARSS’10Multiple Targets Analysis in Layover Multiple Targets Analysis in Layover AreaArea

azi

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ta

zim

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range range

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Estimated Residual Topography

-100

+100m

Single ScatterersLower Double ScatterersHigher Double Scatterers

azi

mu

ta

zim

ut

hh

range range

Multiple Targets Analysis in Layover Multiple Targets Analysis in Layover AreaArea

Detected Single ScatterersDetected Single Scatterers

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Single and double scatterers analysis Single and double scatterers analysis in layover Areain layover Area

Tomographic SAR imaging is able to resolve the interference due to multiple contribution inside the same azimuth/range pixel

This interference typically occurs in urban areas where, because of the layover effect, the buildings are folded down to the ground.

azi

mu

ta

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range range

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Analysis in Layover AreaAnalysis in Layover AreaDetected Single ScatterersDetected Single Scatterers

azi

mu

ta

zim

ut

hh

range range

Estimated Residual Topography

-100

+100m

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Estimated Residual Topography

-100

+100m

Single Scatterers Lower Double Scatterers Higher Double Scatterersbut ….but ….

• Only 17 acquisitionsOnly 17 acquisitions

• Limited orbital tubeLimited orbital tube

•Large incidence angle (Large incidence angle ( 44°) 44°)

Multiple Targets Analysis in Layover Multiple Targets Analysis in Layover AreaArea

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-100m

100m

Amplitude image

RECONSTRUCTED TOPOGRAPHY

Single scatterers

Double scatterers:

bottom

Double scatterers:

upper

Results of the Results of the Wednesday Wednesday

presentation with presentation with spotlight TSX spotlight TSX

datadata

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Results of the Wednesday presentation on TSX Results of the Wednesday presentation on TSX spotlight dataspotlight data

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Comparison between the Edmonton Comparison between the Edmonton and Las Vegas datasets and Las Vegas datasets

slant range

slan

t ra

ng

e

EdmontonNumber of images: 17

Imaging Mode: StripmapAzimuth resolution: 3.3mSlant Range resolution: 1.8m

Incidence Angle: 44°

Las VegasNumber of images: 25

Imaging Mode: HRes SpotlightAzimuth resolution: 1.1mSlant Range resolution: 0.6m

Incidence Angle: 36°

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ConclusionsConclusions• We have carried out an analysis of a TSX data stack over the Edmonton

area (Alberta-Canada).• From the monitoring viewpoint the results show the possibility to achieve a

monitoring of the deformations associated with the presence of past coal seams and with the clay expansion/compaction of clays in the residential areas.

• Higher order analysis for the separation contributions in the Edmonton downtown areas has shown limitations which should be ascribed to the limited number of passes, to the large incidence angle. Large differences of the performances for layover separation wrt to the spotlight results achieved over another areas seem also to be associated with the acquisition mode (stripmap)

FUTURE ACTIVITIES • A deeper interpretation of the results wrt the clay swelling is needed• Processing of more data-stacks, particular spotlights data from TSX and

RADARSAT is necessary to further investigate the potentials of the tomographic technique for layover separation at X and C bands.

THANK YOU