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Real Time and Adaptive Kalman Filter for Joint Nanometric Displacement Estimation, Parameters Tracking and Drift Correction of EFFPI Sensor Systems P. Chawah [email protected] Toulouse Paris Angers Montpelli er Rustre l

Conf limerick 2011

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Page 2: Conf limerick 2011

2P. Chawah [email protected]

Paper context

LINESLaser INterferometry

Earth Strain

OPTICS GEOPHYSICS

for

“Real Time and Adaptive Kalman Filter for Joint Nanometric Displacement Estimation, Parameters Tracking and Drift Correction of EFFPI Sensor Systems"

Page 3: Conf limerick 2011

3P. Chawah [email protected]

Paper context

LINESLaser INterferometry

Earth Strain

OPTICSEFPI sensors

GEOPHYSICS

for

x(t)

SeismometersTiltmetersstrainmeters

“Real Time and Adaptive Kalman Filter for Joint Nanometric Displacement Estimation, Parameters Tracking and Drift Correction of EFFPI Sensor Systems"

Photo-detector

Laser diode

s(t)

Φ(t)

Currentmodulation

I(t)

Q(t)

Kalman filter

arctan

Φ(t)x(t)

novelty

Page 4: Conf limerick 2011

4P. Chawah [email protected]

Current modulation

=

Wavelength modulation

=

Phase modulation m(t)

PD output model

Sinusoidal Fm

“Real Time and Adaptive Kalman Filter for Joint Nanometric Displacement Estimation, Parameters Tracking and Drift Correction of EFFPI Sensor Systems"

Page 5: Conf limerick 2011

5P. Chawah [email protected]

Synchronous quadrature demodulation

AI (t)

AQ (t)

x(t)<<

x(t)<<

x(t)<<

BI (t)

BQ (t)

Homodyne demodulation

“Real Time and Adaptive Kalman Filter for Joint Nanometric Displacement Estimation, Parameters Tracking and Drift Correction of EFFPI Sensor Systems"

Page 6: Conf limerick 2011

6P. Chawah [email protected]

Synchronous quadrature demodulation

2

2

2

2

Virtual displacement carrier

Homodyne demodulation

“Real Time and Adaptive Kalman Filter for Joint Nanometric Displacement Estimation, Parameters Tracking and Drift Correction of EFFPI Sensor Systems"

Page 7: Conf limerick 2011

7P. Chawah [email protected]

Homodyne demodulation

Synchronous quadrature demodulation

2

2

2

2

OPM + temperature instability

+ fiber torsion + pressure

“Real Time and Adaptive Kalman Filter for Joint Nanometric Displacement Estimation, Parameters Tracking and Drift Correction of EFFPI Sensor Systems"

Page 8: Conf limerick 2011

P. Chawah [email protected]

Kalman filter

We need a system that is adaptative is dynamic tracks the Lissajous parameters in real time

8

conic equation+

Elliptic path

Constrained optimization problem

Kalman Filter+

Mathematical model

I(t)

Q(t)

New samples

Update parameters

“Real Time and Adaptive Kalman Filter for Joint Nanometric Displacement Estimation, Parameters Tracking and Drift Correction of EFFPI Sensor Systems"

Page 9: Conf limerick 2011

P. Chawah [email protected]

Kalman filter

9

I(k)

Q(k)

Conic equation for ellipse constraint

+

Kalman Filter+

Conic / Cartesian parameters conversion+

Instantaneous normalization

I’(k)

Q’(k)

Arctan (Q’k / I’k) unwrap Filter m1 xk

222 QγfQγeIγdIQγb)Q(Iγa

“Real Time and Adaptive Kalman Filter for Joint Nanometric Displacement Estimation, Parameters Tracking and Drift Correction of EFFPI Sensor Systems"

Page 10: Conf limerick 2011

10P. Chawah [email protected]

Kalman filter efficiency

Simulated noisy Lissajous plot

Estimation by KF of the clean Lissajous

Behavior of the Kalman filter after a sudden change of the ellipse parameters

“Real Time and Adaptive Kalman Filter for Joint Nanometric Displacement Estimation, Parameters Tracking and Drift Correction of EFFPI Sensor Systems"

Page 11: Conf limerick 2011

11P. Chawah [email protected]

Displacement estimation results

Experimental result: Response of the EFFPI sensor for an impulse displacement (nm)

“Real Time and Adaptive Kalman Filter for Joint Nanometric Displacement Estimation, Parameters Tracking and Drift Correction of EFFPI Sensor Systems"

Validation with apiezo-electric instrument : fig(a) Green: EFFPI displacement estimationBlue: capacitive sensor measurements

fig(b) Blue – Green

2nm peak to peak

Page 12: Conf limerick 2011

12P. Chawah [email protected]

Optimize the sensor : Phase drift correction caused by the temperature

fluctuations Increase the range

– Mechanical solutions,

– Optical solutions,

– Signal processing solutions.

Implement the EFFPI sensor on Geophysical instruments

Validation of the equipment for long time periods in The underground low-noise Laboratory (LSBB Rustrel, France), Seismic sites.

Perspectives

“Real Time and Adaptive Kalman Filter for Joint Nanometric Displacement Estimation, Parameters Tracking and Drift Correction of EFFPI Sensor Systems"