Laser projected acoustic sensor apparatus and method

Patent metadata

Field	Value
Publication number	US-9465109-B2
Application number	US-201213691431-A
Country	US
Kind code	B2
Filing date	Nov 30, 2012
Priority date	Dec 1, 2011
Publication date	Oct 11, 2016
Grant date	Oct 11, 2016

Abstract

A plurality of lasers produces a lattice of projected points. A sensor system detects movement in the projected points in response to an incoming wave.

First claim

What is claimed:

1. A waveform detection apparatus comprising:
a first source of laser light;
a second source of laser light, the first source of laser light and the second source of laser light positioned to constructively interfere with one another to form a lattice of visible bright spots which are brighter than a single laser beam;
an array of optical sensors monitoring the lattice of bright spot, the bright spots movable in response to a passing sound wave front; and
a phase change detector for detecting phase changes in the passing sound wave front from inputs from the optical sensors monitoring the array of visible bright spots.

2. The waveform detection apparatus of claim 1 wherein at least one of the first source of laser light and the second source of laser light are pulsed lasers that sweep to form a plurality of laser beams emanating from the source.

3. The waveform detection apparatus of claim 1 wherein at least one of the first source of laser light and the second source of laser light sweep to form a plurality of laser beams emanating from the source.

4. The waveform detection apparatus of claim 1 wherein the first source of laser light and the second source of laser light are acoustic-optically steered pulsed lasers.

5. The waveform detection apparatus of claim 1 wherein the first source of laser light and the second source of laser light operate at a laser frequency chosen so that the laser beams undergo scattering in sea water.

6. The waveform detection apparatus of claim 1 wherein the lattice formed by the first source of laser light and the second source of laser light is two dimensional.

7. The waveform detection apparatus of claim 1 wherein the lattice formed by the first source of laser light and the second source of laser light is three dimensional.

8. The waveform detection apparatus of claim 1 further comprising a phase correction apparatus for correcting phase differences detected by the optical sensors.

9. The waveform detection apparatus of claim 1 wherein the array of optical sensors are mounted onto a hull of a vessel.

10. The waveform detection apparatus of claim 1 wherein the lattice of bright spots is a holographic array.

11. The waveform detection apparatus of claim 1 further comprising a precompensation module that receives detected phase changes from the phase change detector and calculates phase correction factors to apply to signals associated with the passing sound wave front to convert a distorted passing sound wave front to a substantially non-distorted sound wave front.

12. A method for signal processing comprising:
producing a lattice of points from constructive interference of laser light from a first laser and a second laser;
optically sensing distortion in the shape of a passing sound wave front based upon movement of the lattice of points produced from the first laser and the second laser in response to the passing sound wave front;
detecting the shape of the passing sound wave front from the detected distortion; and
determining at least one correction factor using the detected shape of the passing sound wave front for removing the detected distortion.

13. The method for signal processing of claim 12 wherein the correction factor is a phase difference between one portion of the passing sound wave front and another portion of the passing sound wave front.

14. The method for signal processing of claim 12 wherein the correction factor is applied to correct distortions in the passing sound wave front.

15. The method for signal processing of claim 12 wherein the correction factor is applied to the passing sound wave front as it is received.

16. The method for signal processing of claim 12 wherein the correction factor is applied to a signal representing the passing sound wave front.

17. The method for signal processing of claim 12 wherein the correction factor is applied to a signal representing the passing sound wave front as it is received.

18. The method for signal processing of claim 12 wherein producing a lattice of points includes selecting a laser frequency for the first laser and the second laser where the laser beams undergo scattering in sea water.

19. The method for signal processing of claim 12 wherein optically sensing distortion includes attaching an array of optical sensors to a surface of a vessel.

20. A waveform detection apparatus comprising:
a first source of laser light;
a second source of laser light, the first source of laser light and the second source of laser light positioned to constructively interfere with one another to form a lattice of spots at points of constructive interference between the first source of laser light and the second source of laser light;
a sensor for monitoring spots to detect motion of at least one spot of the lattice of spots, the at least one spot is movable in response to a passing sound wave front; and
detecting the shape of the passing sound wave front from the detected movement of the at least one spot.

21. The waveform detection apparatus of claim 20 wherein the sensor is a range-finding laser that monitors spots in the lattice, the range-finding laser having a frequency which is different than the frequency of the first source of laser light and the second source of laser light.

22. A waveform detection apparatus comprising:
a first source of laser light;
a second source of laser light, the first source of laser light and the second source of laser light positioned to constructively interfere with one another to form a lattice of spots at points of constructive interference between the first source of laser light and the second source of laser light; and
a sensor for monitoring spots to detect motion of the spot, the first source of laser light and the second source of laser light produce a micro-thermocline at least one of the points of intersection.

Assignees

• Lockheed Corp

Inventors

• Fisk Bryan N

Classifications

• G01S7/539

  using analysis of echo signal for target characterisation; Target signature; Target cross-section · CPC title

• G01S15/42 Primary

  Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S15/46) · CPC title

• G01S7/52003

  Techniques for enhancing spatial resolution of targets (G01S7/52046 takes precedence) · CPC title

• G01S7/54

  with receivers spaced apart · CPC title

• G01S7/526

  Receivers · CPC title