Device for determining wind speed comprising a plurality of laser sources

Patent metadata

Field	Value
Publication number	US-9759736-B2
Application number	US-201314395026-A
Country	US
Kind code	B2
Filing date	Apr 15, 2013
Priority date	Apr 16, 2012
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

This device for determining wind speed comprises at least two laser sources emitting beams in different directions that are coplanar and such that each emission direction corresponds to a perpendicular emission direction. Each laser source is associated with focusing optics for focusing the emitted beam, a laser diode for receiving a reflected beam obtained after reflection by a particle present in the air of the corresponding emitted beam, a photodiode for transmitting an interference signal occurring between the emitted beam and the reflected beam, a processor for processing the obtained interference signals, and an optical cavity into which the reflected beam is reinjected in order to obtain an interference with the emitted beam.

First claim

The invention claimed is:

1. A device for determining wind speed comprising:
a first laser source configured to emit a first emitted beam in a first direction;
a second laser source configured to emit a second emitted beam in a second direction that is perpendicular to the first direction and coplanar with the first direction,
first focusing optics configured to focus the first emitted beam toward a first particle present in air, wherein the first laser source is configured to receive a first reflected beam, obtained after reflection of the first emitted beam by the first particle, and transmit a first interference beam based on an interference between the first emitted beam and the first reflected beam,
second focusing optics configured to focus the second emitted beam toward a second particle present in the air, wherein the second laser source is configured to receive a second reflected beam, obtained after reflection of the second emitted beam by the second particle, and transmit a second interference beam based on an interference between the second emitted beam and the second reflected beam,
a first photodiode configured to receive the first interference beam and transmit a first interference signal representative of an optical power of the first interference beam;
a second photodiode configured to receive the second interference beam and transmit a second interference signal representative of an optical power of the second interference beam,
an electronic card configured to process the first and second interference signals, wherein:
the first laser source comprises a first optical cavity into which the first reflected beam is reinjected in order to obtain the first interference beam,
the second laser source comprises a second optical cavity into which the second reflected beam is reinjected in order to obtain the second interference beam, and
the first and second laser sources form a first pair of sources that defines a first orthogonal reference in a plane in which the first and second directions are coplanar, and

third and fourth laser sources that form a second pair of sources that defines a second orthogonal reference in the plane, the first and second orthogonal references thus defined have a same origin.

2. The device according to claim 1 , wherein the first and second orthogonal references are offset with respect to one another by an angle of more than 10°.

3. The device according to claim 2 , wherein the first and second orthogonal references are offset with respect to one another by an angle between 30° and 60°.

4. The device according to claim 3 , wherein the first and second orthogonal references are offset with respect to one another by 45°.

5. The device according to claim 1 , wherein the laser sources are alike.

6. A method for determining wind speed, comprising:
emitting a first emitted beam in a first direction from a first laser diode,
emitting a second emitted beam in a second direction from a second laser diode,
receiving within the first laser diode a first reflected beam reflected by a first particle suspended in air, the first emitted beam interfering with the first reflected beam in the first laser diode,
receiving within the second laser diode a second reflected beam reflected by a second particle suspended in the air, the second emitted beam interfering with the second reflected beam in the second laser diode,
collecting a first modulated signal based on the interfering first emitted beam and first reflected beam,
collecting a second modulated signal based on the interfering second emitted beam and second reflected beam,
amplifying the first and second modulated signals to obtain first and second amplified signals,
sampling the amplified signals to obtain sampled values,
fast Fourier transforming the sampled values to obtain first and second transformed signals,
thresholding the first and second transformed signals,
determining Doppler frequencies for the transformed signals, respectively,
calculating the wind speed based on the Doppler frequencies,
producing a third modulated beam based on an interference, within a third laser diode, between a third emitted beam and a third reflected beam produce by reflection of the third emitted beam by a third particle of the air, and
producing a fourth modulated beam based on an interference, within a fourth laser diode, between a fourth emitted beam and a fourth reflected beam produce by reflection of the fourth emitted beam by a fourth particle of the air, wherein the first and second laser sources are a first pair of sources that defines a first orthogonal reference in a plane in which the first and second directions are coplanar, the third and fourth laser sources are a second pair of sources that defines a second orthogonal reference in the plane, and the first and second orthogonal references thus defined have a same origin.

Assignees

• Epsiline
• Inst Nat Polytechnique Toulouse

Inventors

• Zamama Otmane
• Teysseyre Raphaël
• Perchoux Julien

Classifications

• G01S7/4916

  using self-mixing in the laser cavity · CPC title

• G01S17/87

  Combinations of systems using electromagnetic waves other than radio waves · CPC title

• G01S17/95

  for meteorological use · CPC title

• G01S17/58

  Velocity or trajectory determination systems; Sense-of-movement determination systems · CPC title

• G01P5/26 Primary

  by measuring the direct influence of the streaming fluid on the properties of a detecting optical wave · CPC title