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30-Mar-10 1
Observing the Earth from the space.
A Satellite Radar Application
Álvaro MuñozSupervisor: Victor Hopman
30-Mar-10 2
Introduction
• Background
– Land reclamation
– Soft unconsolidated soil
– Expected subsidence
– Need for monitoring
30-Mar-10 3
Introduction
• Monitoring with Remote Sensing
– Sensors apart from objects
– Measurement--> Energy emitted/reflected
30-Mar-10 4
Introduction• Remote Sensing Techniques
• Source of Energy
• Active/Pasive
• Electromagnetic Spectrum
• Optical/Thermal/Microwave
• Platform
• Manned-Unmanned Plane/Helicopter
• Kites
• Satellite
Active+Microwave+Satellite
30-Mar-10 5
Remote Sensing with Satellite RADAR
• Radar Satellite Orbits
– Elliptical
– Near Polar
– Sun-Synchronous
– Height
• 500-1000 km
30-Mar-10 6
• Active Sensor
– Measurement: Backscattering
Remote Sensing with Satellite RADAR
30-Mar-10 7
• Polarization Dependent
– Example
• Horizontal+Vertical polarization
• Acquisition Geometry
– Azimuth (along track)
– Range (cross track)
Remote Sensing with Satellite RADAR
30-Mar-10 8
• Synthetic Aperture Radar (SAR)
Remote Sensing with Satellite RADAR
30-Mar-10 9
• Complex Waveform
– Parameter: Amplitude• Conventional SAR
• Complex Waveform
– Parameter: Phase• Interferometric SAR
(InSAR)
Remote Sensing with Satellite RADAR
30-Mar-10 10
• Interferometric SAR
Remote Sensing with Satellite RADAR
30-Mar-10 11
• Interferometric SAR
– Major limitation
• Temporal decorrelation
Remote Sensing with Satellite RADAR
30-Mar-10 12
• Persistent Scatterer InSAR (PSInSAR)
Remote Sensing with Satellite RADAR
30-Mar-10 13
• Persistent Scatterer InSAR (PSInSAR)
Remote Sensing with Satellite RADAR
30-Mar-10 14
PSInSAR. Past Case Studies
• Deformation near the Wieliczka Salt Mine in Poland
30-Mar-10 15
Salt Mine in Poland
• Subject and Motivations of the Study
30-Mar-10 16
Salt Mine in Poland
• Available Data
• 51 images ERS-1/2 (ESA)
• 1992 to 2000
•Repeat cycle 34 days
• Single orbit direction
30-Mar-10 17
Salt Mine in Poland• Experimental Results
– PS density
• Maximum=480 PS/km2 (center of Wieliczka)
• Minimum=30 PS/km2 (sparse urbanization areas)
• Average=92 PS/km2
– Comparison with subsidence maps � Agreement
• Leveling data 1970-2000
• PSInSAR data 1992-2000
– Field investigation
• Interpretation of Observations
30-Mar-10 18
Salt Mine in Poland
• Experimental Results
30-Mar-10 19
Salt Mine in Poland
• Conclusions
– Slow subsidence detected by PSInSAR
– Proof of utility of SAR archive
– Agreement leveling data
– More PS density --> Urban areas
– PS on landslide area
• Variability
• Horizontal displacement � limitation of PSInSAR
– Field inspection
• Confirmation of PSInSAR observations
• Hope for risk assessment
30-Mar-10 20
PSInSAR. Recent Case Studies
• PSInSAR Analysis of damages during construction of parking near Koepoortbrug (Delft)
• Filter optimization for PSInSAR analysis
– Houtribdijk
• Monitoring Spoorzone Delft with PSInSAR
30-Mar-10 21
• Subject and Motivations of the Study
Koepoortbrug
30-Mar-10 22
• Available Data
Koepoortbrug
• Envisat (ESA)
• 2003 to 2006
•Every 35 days
• Single orbit direction
30-Mar-10 23
• Experimental Results
Koepoortbrug
• Background: Amplitude SAR
• Overlaid: PS area of interest
30-Mar-10 24
• Conclusions
– Historic data → normal behavior
– Envisat data not suitable. Reasons:
– Very sudden deformations
– Undersampling (35 day repetition rate)
– Possible change of orientation
• Temporal decorrelation
– Repair works
• Solution
– Another data set�
• Higher repetition rate
• Shorter wavelength (improve detectability)
Koepoortbrug
30-Mar-10 25
PSInSAR. Recent Case Studies
• PSInSAR analysis of damages during construction of parking near Koepoortbrug (Delft)
• Filter optimization for PSInSAR analysis
– Houtribdijk
• Monitoring Spoorzone Delft with PSInSAR
30-Mar-10 26
Houtribdijk
• Subject and Motivations of the Study
30-Mar-10 27
• Available Data
Houtribdijk
• Envisat (ESA)
• 2003 to 2007
•Every 35 days
• Single orbit direction
30-Mar-10 28
Houtribdijk
• Experimental Results
30-Mar-10 29
Houtribdijk
• Conclusions
– Denoise filtering smooths time series
– Optimization: Triangular filter. Length 10-12 months
– Similar Performance: Gaussian filter > 12 months
30-Mar-10 30
PSInSAR. Recent Case Studies
• PSInSAR analysis of damages during construction of parking near Koepoortbrug (Delft)
• Filter optimization for PSInSAR analysis
– Houtribdijk
• Monitoring Spoorzone Delft
30-Mar-10 31
• Subject and Motivations of the Study
Spoorzone Delft
30-Mar-10 32
• Available Data
Spoorzone Delft
38--- 40.5° 22.5--- 25.5°38--- 40.5° 22.5--- 25.5°38--- 40.5°38--- 40.5° 22.5--- 25.5°
30-Mar-10 33
• Experimental Results
Spoorzone Delft
30-Mar-10 34
Spoorzone Delft
• Experimental Results
IKEA parking:
• Soil subsidence
30-Mar-10 35
• Experimental Results
– Correction of Geolocation (Reference: AHN&AHN2)
• Vertical offset (estimated height)
Spoorzone Delft
30-Mar-10 36
• Experimental Results
– Correction of Geolocation (Reference: AHN&AHN2)
• Horizontal offset (estimated azimuth and range)
Spoorzone Delft
30-Mar-10 37
• Experimental Results
– Correction of Geolocation (Reference: AHN&AHN2)
• Cross Sections
Spoorzone Delft
30-Mar-10 38
• Experimental Results
– Combination of Ascending/Descending Orbits
Spoorzone Delft
30-Mar-10 39
• Experimental Results
– Combination of Ascending/Descending Orbits
Spoorzone Delft
ASCENDING ORBIT
DESCENDING ORBIT
30-Mar-10 40
• Experimental Results
– Thermal Expansion
Spoorzone Delft
Power of the technique:
• Detect thermal expansion in high buildings
Correlation:
• PSInSAR�thermal theory
30-Mar-10 41
Spoorzone Delft
• Experimental Results
– Thermal Expansion
Vermeer Toren:
• 7,3mm vertical deformation
• (Thermal expansion)
30-Mar-10 42
• Experimental Results
– Detectable Deformation
Spoorzone Delft
Side tilt1 mm
Subsidence1.09 mm
Front tilt7.7 mm
Side tilt1 mm
Subsidence1.09 mm
Front tilt7.7 mm
Side tilt1 mm
Subsidence1.09 mm
Front tilt7.7 mm
Side tilt1 mm
Subsidence1.09 mm
Front tilt7.7 mm
Side tilt1 mm
Subsidence1.09 mm
Front tilt7.7 mm
30-Mar-10 43
Conclusions
• Power – Historic archive (past/future)
– Large coverage
– Cost
– Processing improvements
• Interpretation of observations not straightforward
• PS → physical entities?
PSInSAR can provide mm accuracy in detection of deformation
Monitoring Structures → Damage prevention