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US4867564A
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Apparatus for and method of remotely sensing sub-surface water temperatures
Assignee: General Dynamics Government Systems Corp
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Filing: 1987-06-22
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Granted: 1989-09-19
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Expires: 2007-06-22
Abstract
Abstract The subsurface temperature of a body of water such as an ocean is measured remotely by directing a laser beam deeply into the water and analyzing the resultant Brillouin and Rayleigh backscatter components. Wavelength shifted Brillouin scatter is mixed with the unshifted Rayleigh scatter in a self-heterodyne manner for each volume element of illuminated water and the frequency of the heterodyne signal is measured. This produces the desired temperature-depth profile of the water.
Inventors
- 👤 Harold E. Sweeney
- 👤 Donald A. Leonard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:26
CPC Classifications
G; G01; G01K; G01K13/00; G01K13/10; G01K11/00; G01K11/12
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
87 words
A method of measuring a subsurface property of a body of water from a remote location comprising the steps of: generating a beam of laser light capable of penetrating said water; directing said beam into said water; detecting the Rayleigh and Brillouin backscatter light produced by the interaction of said beam with said water; mixing said Rayleigh and Brillouin light and thereby producing a heterodyne current having a frequency f B ; and measuring the frequency of said heterodyne current for determining said property of said water.
Claim 2
Independent Claim
87 words
A method of measuring a subsurface property of a body of water from a remote location comprising the steps of: generating a beam of laser light capable of penetrating said water; directing said beam into said water; detecting the Rayleigh and Brillouin backscatter light produced by the interaction of said beam with said water; mixing said Rayleigh and Brillouin light and thereby producing a heterodyne current having a frequency f B ; and measuring the frequency of said heterodyne current for determining said property of said water.
Claim 3
Dependent Claim
26 words
The method according to claim 1 with the step of scaling the frequency measurements with time and producing property depth profile of said body of water.
Claim 4
Dependent Claim
12 words
The method according to claim 2 in which said property is temperature.
Claim 5
Dependent Claim
13 words
The method according to claim 3 in which said laser beam is pulsed.
Claim 6
Dependent Claim
19 words
The method according to claim 4 in which said pulsed laser beam is in the blue-green region of light.
Claim 7
Dependent Claim
20 words
The method according to claim 5 in which said remote location is an airplane traveling above the body of water.
Claim 8
Dependent Claim
23 words
The method according to claim 5 in which said remote location is a ship located on the surface of said body of water.
Claim 9
Dependent Claim
54 words
The method according to claim 6 in which said measuring step comprises the steps of: converting said heterodyne current to a signal voltage proportional to f B ; periodically digitizing said signal voltage and generating digitized signal samples; and translating each of said digitized signal samples into a number corresponding to a temperature value.
Claim 10
Dependent Claim
96 words
Apparatus for measuring the subsurface temperature of a body of water from a remote location comprising: means for generating a beam of laser light adapted to penetrate deeply into said body of water; means for detecting components of the Brillouin backscatter produced by said beam; means for detecting components of the Rayleigh backscatter produced by said beam; means for mixing said components of the Brillouin and Rayleigh backscatter and thereby producing an output heterodyne current having a frequency f B ; and means for measuring said frequency for determining the temperature of said body of water.
Claim 11
Dependent Claim
96 words
Apparatus for measuring the subsurface temperature of a body of water from a remote location comprising: means for generating a beam of laser light adapted to penetrate deeply into said body of water; means for detecting components of the Brillouin backscatter produced by said beam; means for detecting components of the Rayleigh backscatter produced by said beam; means for mixing said components of the Brillouin and Rayleigh backscatter and thereby producing an output heterodyne current having a frequency f B ; and means for measuring said frequency for determining the temperature of said body of water.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-09-18 | 1993-03-20 | 1993-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-18 | 1997-03-20 | 1997-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-18 | 2001-03-20 | 2001-09-19 | $7700.00 | Window Closed / Lapsed |