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US3903520A
Expired / Lapsed
US
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Underwater object locating system
Assignee: United States Department of the Navy
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Filing: 1960-08-11
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Granted: 1975-09-02
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Expires: 1980-08-11
Abstract
Abstract 1. In a method for determining the presence in the ocean of a submerged object which has a temperature that is different from that of the contiguous seawater, the steps of RADIATING A DIRECTIONAL BEAM OF ELECTROMAGNETIC WAVES OF A PRESELECTED FREQUENCY TOWARDS THE OCEAN SURFACE AT AN ANGLE SUCH THAT A PORTION OF SAID ELECTROMAGNETIC WAVES IS REFLECTED FROM THE OCEAN SURFACE AND A PORTION ENTERS THE OCEAN, SAID PRESELECTED FREQUENCY BEING CHOSEN SUCH THAT SAID PORTION OF ELECTROMAGNETIC WAVES WHICH ENTER THE OCEAN IS PROPAGATED AN APPRECIABLE DISTANCE THEREIN, THE ELECTROMAGNETIC WAVES WHICH ARE SO PROPAGATED WHEN THEY ENCOUNTER VARIATIONS IN THE INDEX OF REFRACTION OF THE SEAWATER CAUSED BY THE TEMPERATURE DIFFERENCE BETWEEN THIS WATER AND THE SUBMERGED OBJECT BEING REFLECTED AT THESE SUBSURFACE LOCATIONS WITH THEIR FREQUENCY ALTERED AS A CONSEQUENCE OF THIS INTERACTION AND, THEREAFTER, EMERGE FROM SAID OCEAN; DETECTING THE ELECTROMAGNETIC WAVES WHICH ARE REFLECTED FROM THE OCEAN SURFACE AND ANY ELECTROMAGNETIC WAVES WHICH EMERGE FROM SAID OCEAN; AND ANALYZING THE FREQUENCY OF THE ELECTROMAGNETIC WAVES SO DETECTED TO DETERMINE THE PRESENCE OF ANY ELECTROMAGNETIC WAVES WHICH HAVE A FREQUENCY DIFFERENT FROM THAT OF SAID PRESELECTED FREQUENCY.
Inventors
- 👤 Arnold A Shostak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 07:31
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/50; B; B63; B63C; B63C11/00; B63C11/48; G01S13/003
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
192 words
In a method for determining the presence in the ocean of a submerged object which has a temperature that is different from that of the contiguous seawater, the steps of radiating a directional beam of electromagnetic waves of a preselected frequency towards the ocean surface at an angle such that a portion of said electromagnetic waves is reflected from the ocean surface and a portion enters the ocean, said preselected frequency being chosen such that said portion of electromagnetic waves which enter the ocean is propagated an appreciable distance therein, the electromagnetic waves which are so propagated when they encounter variations in the index of refraction of the seawater caused by the temperature difference between this water and the submerged object being reflected at these subsurface locations with their frequency altered as a consequence of this interaction and, thereafter, emerge from said ocean; detecting the electromagnetic waves which are reflected from the ocean surface and any electromagnetic waves which emerge from said ocean; and analyzing the frequency of the electromagnetic waves so detected to determine the presence of any electromagnetic waves which have a frequency different from that of said preselected frequency.
Claim 2
Dependent Claim
192 words
In a method for determining the presence in the ocean of a submerged object which has a temperature that is different from that of the contiguous seawater, the steps of radiating a directional beam of electromagnetic waves of a preselected frequency towards the ocean surface at an angle such that a portion of said electromagnetic waves is reflected from the ocean surface and a portion enters the ocean, said preselected frequency being chosen such that said portion of electromagnetic waves which enter the ocean is propagated an appreciable distance therein, the electromagnetic waves which are so propagated when they encounter variations in the index of refraction of the seawater caused by the temperature difference between this water and the submerged object being reflected at these subsurface locations with their frequency altered as a consequence of this interaction and, thereafter, emerge from said ocean; detecting the electromagnetic waves which are reflected from the ocean surface and any electromagnetic waves which emerge from said ocean; and analyzing the frequency of the electromagnetic waves so detected to determine the presence of any electromagnetic waves which have a frequency different from that of said preselected frequency.
Claim 3
Dependent Claim
180 words
In a method for determining the presence of an object submerged in the ocean, which object radiates acoustic waves incidental to its normal operation, the steps of directing an incident beam of electromagnetic waves whose frequency is being cylcically varied about a preselected value toward said ocean surface at an angle such that a portioN of said electromagnetic waves is reflected from the ocean surface and a portion enters the ocean and is propagated therein for a distance determined by the frequency of said electromagnetic waves, said preselected frequency value being chosen to permit said propagation to occur over a significant distance, the electromagnetic waves, which are so propagated when they encounter an area of the ocean wherein said acoustic waves are present interacting with said acoustic waves and being reflected back out of said ocean; and analyzing the frequencies of all of the electromagnetic reflected waves thereby to determine the presence of a component whose frequency differs from that of the incident beam by an amount related to the frequency of the acoustic waves radiated from said submerged object.
Claim 4
Dependent Claim
180 words
In a method for determining the presence of an object submerged in the ocean, which object radiates acoustic waves incidental to its normal operation, the steps of directing an incident beam of electromagnetic waves whose frequency is being cylcically varied about a preselected value toward said ocean surface at an angle such that a portioN of said electromagnetic waves is reflected from the ocean surface and a portion enters the ocean and is propagated therein for a distance determined by the frequency of said electromagnetic waves, said preselected frequency value being chosen to permit said propagation to occur over a significant distance, the electromagnetic waves, which are so propagated when they encounter an area of the ocean wherein said acoustic waves are present interacting with said acoustic waves and being reflected back out of said ocean; and analyzing the frequencies of all of the electromagnetic reflected waves thereby to determine the presence of a component whose frequency differs from that of the incident beam by an amount related to the frequency of the acoustic waves radiated from said submerged object.
References Cited (Backward Citations)
US3153236A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-01 | 1979-03-03 | 1979-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-01 | 1983-03-03 | 1983-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-01 | 1987-03-03 | 1987-09-02 | $7700.00 | Window Closed / Lapsed |