Patent US3922631A successfully refreshed from Google Patents.
US3922631A
Expired / Lapsed
US
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Underwater intrusion detecting system
Assignee: United States Department of the Navy
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Filing: 1960-06-20
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Granted: 1975-11-25
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Expires: 1980-06-20
Abstract
Abstract 1. An acoustic barrier for detecting and classifying a body intruding into a protected volume of water comprising a high resolution active sonar apparatus including a transmitting transducer submerged in the protected volume of water and having a vertically oriented fan shape directivity pattern with its principal axis slanted toward a bounding surface, means for rotating said transmitting transducer in azimuth about a vertical axis, means for pulsing said transmitting transducer t times per second, and means for displaying in PPI presentation the flutter echoes returned from said bounding surface with spot positions in the presentation being functions of the azimuth and slant ranges of the echo origins, said displaying means including a receiving transducer having a vertically oriented fan shape directivity pattern with its principal axis slanted toward said bounding surface and a beam width in azimuth in degrees equal to 2 theta , and said receiving transducer being mounted for rotation in assembly with said transmitting transducer and being so oriented that its principal axis lags behind the principal axis of said transmitting transducer by an azimuthal angle of theta * where theta omega divided by t WHEREIN omega EQUALS THE ANGULAR VELOCITY IN DEGREES PER SECOND AT WHICH SAID TRANSDUCERS ARE ROTATED.
Inventors
- 👤 John H Thompson
- 👤 David S Sims
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 08:27
CPC Classifications
G; G01; G01S; G01S15/00; G01S15/02; G01S15/06; G01S15/08; G01S15/10; G01S15/101; G01S7/00; G01S7/52; G01S7/56; G01S7/62; G01S7/6218; G01S7/6227
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
204 words
An acoustic barrier for detecting and classifying a body intruding into a protected volume of water comprising a high resolution active sonar apparatus including a transmitting transducer submerged in the protected volume of water and having a vertically oriented fan shape directivity pattern with its principal axis slanted toward a bounding surface, means for rotating said transmitting transducer in azimuth about a vertical axis, means for pulsing said transmitting transducer t times per second, and means for displaying in PPI presentation the flutter echoes returned from said bounding surface with spot positions in the presentation being functions of the azimuth and slant ranges of the echo origins, said displaying means including a receiving transducer having a vertically oriented fan shape directivity pattern with its principal axis slanted toward said bounding surface and a beam width in azimuth in degrees equal to 2 theta , and said receiving transducer being mounted for rotation in assembly with said transmitting transducer and being so oriented that its principal axis lags behind the principal axis of said transmitting transducer by an azimuthal angle of theta * where theta omega divided by t wherein omega equals the angular velocity in degrees per second at which said transducers are rotated.
Claim 2
Dependent Claim
204 words
An acoustic barrier for detecting and classifying a body intruding into a protected volume of water comprising a high resolution active sonar apparatus including a transmitting transducer submerged in the protected volume of water and having a vertically oriented fan shape directivity pattern with its principal axis slanted toward a bounding surface, means for rotating said transmitting transducer in azimuth about a vertical axis, means for pulsing said transmitting transducer t times per second, and means for displaying in PPI presentation the flutter echoes returned from said bounding surface with spot positions in the presentation being functions of the azimuth and slant ranges of the echo origins, said displaying means including a receiving transducer having a vertically oriented fan shape directivity pattern with its principal axis slanted toward said bounding surface and a beam width in azimuth in degrees equal to 2 theta , and said receiving transducer being mounted for rotation in assembly with said transmitting transducer and being so oriented that its principal axis lags behind the principal axis of said transmitting transducer by an azimuthal angle of theta * where theta omega divided by t wherein omega equals the angular velocity in degrees per second at which said transducers are rotated.
Claim 3
Dependent Claim
25 words
The system set forth in claim 1 wherein said transmitting transducer has a line of focus lying substantially in the plane of said bounding surface.
Claim 4
Dependent Claim
153 words
In a pulse-echo catacoustic system for detecting the intrusion of a body into a volume of water comprising water submerged acoustic transducer means having a vertically oriented fan shape directivity pattern with its principal axis slanted toward a surface bounding said volume of water for transmitting an acoustic signal pulse and for receiving flutter echoes returned from said bounding surface for a time interval equal to the transit time of a pulse-echo from a selected maximum slant range, a receiver circuit connected to said transducer means and operative to provide an output signal of substantially constant amplitude from the received flutter echoes, an alertiNg system, and a time-constant network connected between the output of said receiver circuit and said alerting system for energizing said alerting system whenever the amplitude of said output signal falls below a selected value for an interval of time at least equal to the response time of said network.
Claim 5
Dependent Claim
153 words
In a pulse-echo catacoustic system for detecting the intrusion of a body into a volume of water comprising water submerged acoustic transducer means having a vertically oriented fan shape directivity pattern with its principal axis slanted toward a surface bounding said volume of water for transmitting an acoustic signal pulse and for receiving flutter echoes returned from said bounding surface for a time interval equal to the transit time of a pulse-echo from a selected maximum slant range, a receiver circuit connected to said transducer means and operative to provide an output signal of substantially constant amplitude from the received flutter echoes, an alertiNg system, and a time-constant network connected between the output of said receiver circuit and said alerting system for energizing said alerting system whenever the amplitude of said output signal falls below a selected value for an interval of time at least equal to the response time of said network.
Claim 6
Dependent Claim
49 words
The system set forth in claim 3 including a cathode ray indicator tube connected to have the intensity of its electron beam controlled by said output signal, and means for unblanking said indicator tube and for enabling said alerting system only during said time interval of flutter echo reception.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-24 | 1979-05-26 | 1979-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-24 | 1983-05-26 | 1983-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-24 | 1987-05-26 | 1987-11-25 | $7700.00 | Window Closed / Lapsed |