Demonstration of TerraSAR-X ScanSAR Persistent Scatterer Interferometry

F. Rodriguez Gonzalez(1), R. Brcic(1), Nestor Yague-Martinez(2), R. Shau(1), A. Parizzi(1), N. Adam(1)

(1) German Aerospace Center (DLR) (2) Technische Universität München (TUM)

> Fringe 2015 Workshop > ESA - ESRIN > 23 – 27 March 2015 DLR.de • Chart 1

• Preparation for Sentinel-1 TopSAR acquisition mode • Wide Area PSI demonstration with TerraSAR-X ScanSAR Mode

Terrafirma – ESA Project

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TopSAR Mode ScanSAR Mode

ESRIN/Contract no. C19366/05/I-EC/DLR

TerraSAR-X ScanSAR Mode

• Azimuth variant spectrum -> Coregistration requirement

Terrafirma – ESA Project

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Sentinel-1 TopSAR Mode

~320 Hz

~475 Hz ~4400 Hz

~2000 Hz

∆𝑓𝑓𝐷𝐷𝐷𝐷𝐵𝐵𝐵𝐵𝑎𝑎𝑎𝑎

≈ 14 ∆𝑓𝑓𝐷𝐷𝐷𝐷𝐵𝐵𝐵𝐵𝑎𝑎𝑎𝑎

≈ 4

Test Site: Lake Mead - Hoover Dam

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• Lake Mead water elevation

Test Site: Lake Mead - Hoover Dam

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Water level data source : Bureau of reclamation. http://www.usbr.gov

Dataset: TerraSAR-X ScanSAR Stack

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Dataset: TerraSAR-X ScanSAR Stack

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Dataset: TerraSAR-X ScanSAR Stack

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INT_8957

Slave Acquisition 2009-01-25

Effective Baseline 40.4 m

Height of Ambiguity -93.8 m

Slave Acquisition 2009-11-29

Effective Baseline 51.6 m

Height of Ambiguity -73.5 m

INT_13633

Dataset: TerraSAR-X ScanSAR Stack

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INT_11462

Slave Acquisition 2009-07-09

Effective Baseline 107.7 m

Height of Ambiguity -35.2 m

• Partition of scene for SCR-based detection

PSI Detection

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PSI Detection

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• Effect of burst synchronization on stack

2.3 km

• Point target response squint

• Master scene

• Slave scene

PSI Arc Estimation

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𝑠𝑠 𝑡𝑡, 𝜏𝜏 = 𝑠𝑠𝑟𝑟(𝜏𝜏 − 𝜏𝜏0) ∙ 𝑠𝑠𝑟𝑟(𝑡𝑡 − 𝑡𝑡0 − 𝑘𝑘 ∙ (𝜏𝜏 − 𝜏𝜏0)) ∙

𝑒𝑒𝑒𝑒𝑒𝑒 −𝑗𝑗 4𝜋𝜋𝜆𝜆𝑟𝑟0 ∙ 𝑒𝑒𝑒𝑒𝑒𝑒 −𝑗𝑗𝑗𝑗𝑗𝑓𝑓0(𝑐𝑐𝑐𝑐𝑠𝑠𝑐𝑐 − 1)(𝜏𝜏 − 𝜏𝜏0) ∙ 𝑒𝑒𝑒𝑒𝑒𝑒 𝑗𝑗𝑗𝑗𝑗𝑓𝑓𝐷𝐷𝐷𝐷 (𝑡𝑡 − 𝑡𝑡0)

𝜙𝜙1𝑀𝑀 = −4𝑗𝑗𝜆𝜆 𝑟𝑟01

𝑀𝑀 + 𝑗𝑗𝑗𝑓𝑓𝐷𝐷𝐷𝐷,1𝑀𝑀 Δ𝑡𝑡𝑃𝑃𝑃𝑃𝑃𝑃,1

𝜙𝜙1𝑆𝑆 = −4𝑗𝑗𝜆𝜆 𝑟𝑟01

𝑆𝑆 + 𝑗𝑗𝑗𝑓𝑓𝐷𝐷𝐷𝐷,1𝑆𝑆 (Δ𝑡𝑡𝑃𝑃𝑃𝑃𝑃𝑃,1 − Δ𝑡𝑡𝐷𝐷𝐶𝐶)

Δ𝑡𝑡𝐷𝐷𝐶𝐶

Δ𝑡𝑡𝑃𝑃𝑃𝑃𝑃𝑃,1

• Interferogram

• Double difference -> arc estimation

PSI Arc Estimation

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𝜙𝜙1𝐼𝐼 = 𝜙𝜙1𝑀𝑀 − 𝜙𝜙1𝑆𝑆 = −4𝑗𝑗𝜆𝜆

𝑟𝑟01𝑀𝑀 − 𝑟𝑟01

𝑆𝑆 − 𝑗𝑗𝑗 𝑓𝑓𝐷𝐷𝐷𝐷,1𝑀𝑀 − 𝑓𝑓𝐷𝐷𝐷𝐷,1

𝑆𝑆 Δ𝑡𝑡𝑃𝑃𝑃𝑃𝑃𝑃,1 + 𝑗𝑗𝑗𝑓𝑓𝐷𝐷𝐷𝐷,1𝑆𝑆 Δ𝑡𝑡𝐷𝐷𝐶𝐶

= −4𝜋𝜋𝜆𝜆∆𝑟𝑟0,1

𝑀𝑀→𝑆𝑆 − 𝑗𝑗𝑗∆𝑓𝑓𝐷𝐷𝐷𝐷,1𝑀𝑀→𝑆𝑆Δ𝑡𝑡𝑃𝑃𝑃𝑃𝑃𝑃,1 + 𝑗𝑗𝑗𝑓𝑓𝐷𝐷𝐷𝐷,1

𝑆𝑆 Δ𝑡𝑡𝐷𝐷𝐶𝐶

𝜙𝜙1𝐼𝐼 − 𝜙𝜙2𝐼𝐼 = −4𝑗𝑗𝜆𝜆 ∆𝑟𝑟0,1

𝑀𝑀→𝑆𝑆 − ∆𝑟𝑟0,2𝑀𝑀→𝑆𝑆

−𝑗𝑗𝑗∆𝑓𝑓𝐷𝐷𝐷𝐷,1

𝑀𝑀→𝑆𝑆𝛥𝛥𝑡𝑡𝑃𝑃𝑃𝑃𝑃𝑃,1+ 𝑗𝑗𝑗∆𝑓𝑓𝐷𝐷𝐷𝐷,2𝑀𝑀→𝑆𝑆Δ𝑡𝑡𝑃𝑃𝑃𝑃𝑃𝑃,2

+ 𝑗𝑗𝑗(𝑓𝑓𝐷𝐷𝐷𝐷,1

𝑆𝑆 −𝑓𝑓𝐷𝐷𝐷𝐷,2𝑆𝑆 )Δ𝑡𝑡𝐷𝐷𝐶𝐶

Model (∆v, ∆h)

Sub-pixel position

Controlled by ScanSAR / TOPS corregistration

• Simplified estimation: linear fit of phase-versus-height for a target area • Limitations, valid for processor initial testing

Stratification Mitigation

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Raw extracted PS phase PS phase after stratification mitigation

• Effect in arcs estimates and network construction • Higher coherence • Arcs between different heighs, higher redundancy / control

Stratification Mitigation

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Arc quality and network construction without stratification mitigation

Arc quality and network construction with stratification mitigation

• Further steps remain algorithmically unchanged • Reference network inversion • APS estimation • Final estimations

PSI Processing

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Linear Deformation Rate

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Linear deformation (ramp compensated)

Without stratification mitigation

Linear Deformation Rate

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• Cavalié, O., M.-P. Doin, C. Lasserre, and P. Briole (2007), Ground motion measurement in the Lake Mead area, Nevada, by differential synthetic aperture radar interferometry time series analysis: Probing the lithosphere rheological structure, J. Geophys. Res., 112, B03403, doi:10.1029/2006JB004344.

Linear Deformation Rate

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Linear Deformation Rate

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• Residual topography between

• STRM • Acquired in February 2000 • Lake Mead water level : 370 m (1213.79 feet, monthly average)*

• Master scene • Acquired in December 2009 • Lake Mead water level : 334 m (1096.30 feet, monthly average)*

Residual Topography

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* Water level data source : Bureau of reclamation. http://www.usbr.gov

Residual Topography

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Residual Topography

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Spatial average PS coherence

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• PS Coherence evaluated in 200 Hz Doppler Centroid bins

PS coherence statistics

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Spatial average PS Density

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„Secondary PS“

• Partition of scene for SCR-based detection

PSI Detection

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• Extraction at sub-pixel position detected in another burst

→ Every secondary PS has a corresponding primary PS

→ But with a different Doppler Centroid

Secondary PS

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Primary

Secondary

• Primary – Secondary PS -pairs

Secondary PS

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~2000 Hz Intra Beam ~ 1500 Hz Inter Beam ~ 500 Hz Inter Beam

Secondary PS Estimates

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~2000 Hz Intra Beam ~ 1500 Hz Inter Beam ~ 500 Hz Inter Beam

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Secondary PS

• Coherence loss versus power loss

~ 1500 Hz Inter Beam ~ 500 Hz Inter Beam

• Std. deviation of phase residuals

Behaviour of Scatterers

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0.7 < Coherence < 0.9 0.9 < Coherence < 1.0

• Primary – Secondary PS -pairs

Secondary PS

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~2000 Hz Intra Beam ~ 1500 Hz Inter Beam ~ 500 Hz Inter Beam

• Potential uses of Primary – Secondary pairs • Potential use of PS Enhanced Spectral Diversity

Secondary PS

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ESD

PS

ESD

~2000Hz Intra Beam ~1500 Hz Inter Beam ~500Hz Inter Beam

• Demonstration of TerraSAR-X ScanSAR PSI

• Revisit available ScanSAR stacks

• Strategy to exploit PS ESD to control coregistration after PS detection

• Further work

• Explotation of PSI APS for DSI processing

• Study the overlap area in urban areas • Explotaiton of Sentinel-1

Conclusions and Outlook

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