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Ionospheric Calibration Scheme for the BIOMASS Pol-InSAR Data ...

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<strong>Ionospheric</strong> <strong>Calibration</strong> <strong>Scheme</strong> <strong>for</strong><br />

<strong>the</strong> <strong>BIOMASS</strong> <strong>Pol</strong>-<strong>InSAR</strong> <strong>Pol</strong> <strong>InSAR</strong> <strong>Data</strong> Space<br />

Jun Su Kim, Andreas Danklmayer & Konstantinos P. Papathanassiou<br />

Microwave and Radar Institute<br />

German Aerospace Center<br />

Microwaves and Radar Institute


Framework & Constrains<br />

Intensity <strong>Pol</strong>arimetry Interferometry<br />

Scipal K. “The <strong>BIOMASS</strong> Mission –<br />

Status and results from Phase-A activities”<br />

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<strong>BIOMASS</strong><br />

biomass<br />

TO OBSERVE FOREST <strong>BIOMASS</strong><br />

FOR A BETTER UNDERSTANDING OF THE CARBON CYCLE<br />

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Correction Techniques<br />

Single Image Approaches<br />

Interferometric App.<br />

Range (Dispersion) Based Azimuth (Spatial Var.) Based<br />

►Auto Focus (AF)<br />

►TEC AF (Δt)<br />

►Sub-Look Co-registration<br />

►Non-Coherent<br />

►Coherent (CS’s)<br />

►Faraday Rotation<br />

► Differential Faraday Rotation<br />

► Interferometric Phase Distortion<br />

► Spatial Co-registration (Coherent)<br />

► Split Bandwidth Techniques<br />

► PS<br />

► Auto Focus (AF)<br />

► Maximum Contrast<br />

► Phase Gradient<br />

►Phase Gradient Estimation (CS’s)<br />

►Sub-Look (AF) Co-registration<br />

►Non-Coherent<br />

►Coherent (CS’s)<br />

►Maximum Contrast AF<br />

►Multi-Squint<br />

►Spatial Co-registration<br />

►PS<br />

Small Scale<br />

Microwaves and Radar Institute


Correction Techniques<br />

Single Image Approaches<br />

Interferometric App.<br />

Range (Dispersion) Based Azimuth (Spatial Var.) Based<br />

►Auto Focus (AF)<br />

►TEC AF (Δt)<br />

►Sub-Look Co-registration<br />

►Non-Coherent<br />

►Coherent (CS’s)<br />

►Faraday Rotation<br />

► Differential Faraday Rotation<br />

► Interferometric Phase Distortion<br />

► Spatial Co-registration (Coherent)<br />

► Split Bandwidth Techniques<br />

► PS<br />

► Auto Focus (AF)<br />

► Maximum Contrast<br />

► Phase Gradient<br />

►Phase Gradient Estimation (CS’s)<br />

►Sub-Look (AF) Co-registration<br />

►Non-Coherent<br />

►Coherent (CS’s)<br />

►Maximum Contrast AF<br />

►Multi-Squint<br />

►Spatial Co-registration<br />

►PS<br />

Small Scale<br />

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Effects on <strong>Pol</strong>-<strong>InSAR</strong> <strong>Pol</strong> <strong>InSAR</strong>: : coherence region<br />

P-band E-SAR Mawas<br />

Differential<br />

Faraday Rotation<br />

3, 6, 15, 30, 60, 90, 120, 150<br />

degrees<br />

Example: Homogeneous Tropical Forest<br />

Azimuth shift Interferometric<br />

phase<br />

0 to 4 pixels,<br />

0.4 pixel step<br />

Rapid Expansion Decorrelation<br />

+ additional phase<br />

Every 60 degree<br />

Rotation<br />

What if multi-baseline?<br />

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Structure<br />

<strong>Data</strong> FR<br />

estimation<br />

Interferometric<br />

phase Combined<br />

Azimuth<br />

Shift<br />

Tomography?<br />

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<strong>Data</strong> Set Used (ALASKA; ALOS)<br />

TEC on 1 April 2007<br />

Time of<br />

Acquisition<br />

From HAARP homepage<br />

Fairbanks<br />

Interferometic<br />

Info.<br />

•1st April and 17th May, 2007<br />

at 7:28 UTM<br />

•Baselines:<br />

44.8, 46.6, 54.6 and 81.3m<br />

(respectively)<br />

Highway Beaver Collville<br />

Pauli decomposed images<br />

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Faraday rotation: <strong>the</strong>ory<br />

S(Ω) �<br />

From Wikimedia Commons<br />

Disturbance on quad-pol<br />

Not reciprocal!<br />

RSR<br />

SAR<br />

� cos Ω<br />

R � ��<br />

��<br />

sin Ω<br />

sin Ω �<br />

cos Ω<br />

��<br />

�<br />

Determination of FR ���<br />

�<br />

eB<br />

�κˆ<br />

Ω � � TEC<br />

2<br />

cmf0<br />

�<br />

B<br />

e<br />

�<br />

: Konstant 40.31m : Charge of electron<br />

m : Mass of electron<br />

κˆ<br />

f0<br />

: carrier frequency<br />

c<br />

: Total electron contents<br />

3 /s2 : Geomagnetic field<br />

: Unit propagation vector<br />

: Speed of light TEC<br />

S<br />

S<br />

S<br />

S<br />

hh<br />

hv<br />

vh<br />

vv<br />

Correction of Scattering Matrix<br />

2<br />

2<br />

�Ω� �<br />

cos ΩShh<br />

� sin ΩSvv,<br />

���cos ٠sin �Shh<br />

� Svv<br />

��<br />

����cos ٠sin �Shh<br />

� Svv<br />

�<br />

2<br />

2<br />

�Ω���sin ΩShh<br />

� cos ΩSvv<br />

Sxx,<br />

� S<br />

xx<br />

Microwaves and Radar Institute<br />

,


Faraday rotation: estimation<br />

Bickel & Bates � estimator<br />

Ω �<br />

1<br />

4<br />

arg<br />

� * � S<br />

LR RL S<br />

Estimation in <strong>the</strong> circular basis<br />

Highway Beaver Collville<br />

Fairbanks<br />

Microwaves and Radar Institute


Faraday rotation: differential estimation<br />

Differential estimations<br />

ΔΩ � Ω � Ω<br />

1<br />

Highway Beaver Collville<br />

2<br />

Fairbanks<br />

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Faraday rotation: results (HH-HV (HH HV coherence)<br />

Be<strong>for</strong>e After Be<strong>for</strong>e After<br />

Fairbanks Highway<br />

Be<strong>for</strong>e After<br />

Beaver<br />

Be<strong>for</strong>e After<br />

Collville<br />

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Global accuracy of TEC from FR (P-band) (P band)<br />

SNR=30dB, L=10,000<br />

Descending orbit<br />

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Azimuth shift: <strong>the</strong>ory<br />

Azimuthal Image Shifts<br />

in TEC gradient regions<br />

Determination of azimuth shift<br />

v<br />

Δa � 2�<br />

Δa<br />

vpiercing<br />

piercing<br />

D<br />

f<br />

PRF<br />

cf<br />

PRF : Pulse repetition frequency<br />

D f<br />

x<br />

: Azimuth shift [pixel]<br />

: Velocity of piercing point<br />

: Doppler rate<br />

: azimuth distance<br />

Azimuth shift sensitivity<br />

0<br />

d<br />

� ΔTEC<br />

dx<br />

P-band, PRF: 600 Hz, D f<br />

211 Hz/s : 0.70 pixel/TECU/100km<br />

L-band, PRF: 1900 Hz, D f 576 Hz/s : 0.29 pixel/TECU/100km<br />

Satellite<br />

orbit<br />

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Azimuth shift: estimation<br />

Time-Doppler relation<br />

Shift of Doppler frequency<br />

and phase: 5TECU/100km<br />

d<br />

dx<br />

ΔTEC<br />

Beaver Collville<br />

Microwaves and Radar Institute


Azimuth shift: result ( (�� comparison)<br />

Be<strong>for</strong>e After<br />

Collville<br />

��-histogram<br />

Shift FR<br />

Estimation of<br />

<strong>the</strong> white<br />

boundary only<br />

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Interferometric<br />

Determination of<br />

interferometric phase ���<br />

φ<br />

Sensitivity<br />

�ΔTEC<br />

� 4�<br />

cf<br />

phase: <strong>the</strong>ory<br />

L-band:<br />

13.30 rad./TECU= 2.12 cycle/TECU<br />

1 cycle ~ 0.47 TECU<br />

P-band:<br />

38.82 rad./TECU= 6.18 cycle/TECU<br />

1 cycle ~ 0.16 TECU<br />

0<br />

Interferograms<br />

under ionospheric<br />

Collville Beaver<br />

phases<br />

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Interferometric<br />

phase: correction and results<br />

- =<br />

Original FR Corrected phase<br />

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Interferometric<br />

Estimation accuracy<br />

using polarimetry (FR)<br />

phase and TEC in P-band P band<br />

Oberpfaffen<br />

-hofen<br />

Alaska<br />

W=6MHz, �=30°, az. Res=10m<br />

Amazon<br />

Corresponding stddev. on<br />

interferometry<br />

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Combined estimation: <strong>the</strong>ory<br />

Varying ionosphere<br />

Ω<br />

N<br />

�<br />

�<br />

�11�1�TEC Satellite orbit<br />

Mean -> FR<br />

Slant -> shift<br />

�TEC<br />

12<br />

� � 2<br />

�x<br />

L N �1�<br />

�<br />

eB �κˆ<br />

� � �<br />

cmf<br />

2<br />

0<br />

�<br />

�<br />

L<br />

Divide Ionosphere<br />

into N segments<br />

6<br />

Coherent length = L<br />

TEC1 TEC2 3<br />

�<br />

TEC � 1<br />

2<br />

Measure of FR Measure of Azimuth shift<br />

TEC � TECN<br />

� �T TEC TEC � TEC<br />

�12�N� �<br />

TEC<br />

� � C<br />

� � E T 1 1 1 �<br />

N �1<br />

�<br />

N<br />

Microwaves and Radar Institute


Combined estimation: estimation (phase and coherence)<br />

�<br />

� Ω � �G<br />

� ��<br />

� �<br />

� �<br />

�<br />

� Δa<br />

� � 0<br />

Ω<br />

G<br />

0<br />

Δa<br />

TEC � �<br />

�<br />

�<br />

�<br />

�<br />

�<br />

TEC � C d<br />

Coherence comparison:<br />

Equation to be solved<br />

Solution:<br />

�a by 3-ways<br />

� � � �<br />

T �1<br />

�1<br />

T �1<br />

G C G G<br />

D<br />

D<br />

obs<br />

Interferometric<br />

phase correction<br />

FR only Combined<br />

Microwaves and Radar Institute


Tomography: test<br />

Geometry of problem<br />

Height<br />

We used azimuth sub-look parallax.<br />

a priori posterior<br />

Azimuth<br />

Observation<br />

a prior<br />

posterior<br />

Azimuth<br />

Range<br />

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Conclusion<br />

Adversary<br />

effects<br />

<strong>Pol</strong>arimetry FR estimation<br />

Correction approach<br />

Azimuth shift Image correlation and resampling<br />

Interferometric<br />

(Limit)<br />

(Limited to quad-pol)<br />

phase From �TEC estimation (Still remaining azimuth drift)<br />

• The combined estimator per<strong>for</strong>ms better.<br />

Using �FR and/or �FR + azimuth shift<br />

(No way of getting ground truth)<br />

• The parametric estimation can be extended to 3rd dimension.<br />

• What can we do with single-pol interferometric phase, or tropical <strong>for</strong>est<br />

(<strong>BIOMASS</strong>) of Equator?<br />

Microwaves and Radar Institute

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