US5339684A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gravity aided inertial navigation system
Assignee: Lockheed Martin Corp
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Filing: 1991-12-10
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Granted: 1994-08-23
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Expires: 2011-12-10
Abstract
Abstract An autonomous covert Inertial Navigation System uniquely suited for underwater applications wherein Schuler and siderial errors are bounded without external navigation aids or active instrumentation of ground speed is achieved by integrating a conventional Inertial Navigation System with a gravity gradiometer capable of measuring gravity field components independently of platform accelerations.
Inventors
- 👤 Albert Jircitano
- 👤 Daniel E. Dosch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:22
CPC Classifications
G; G01; G01C; G01C21/00; G01C21/10; G01C21/12; G01C21/16; G01C21/183; G01C21/185; G01C21/166; G01C21/188
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
50 words
A navigation system, comprising: a gravity gradiometer means; a three axis inertial position determining means including a vertical accelerometer means; a vertical displacement sensor; and an optimal filter means for integrating electronic outputs from said gravity gradiometer means, said three axis inertial position determining means and said vertical displacement sensor.
Claim 2
Dependent Claim
50 words
A navigation system, comprising: a gravity gradiometer means; a three axis inertial position determining means including a vertical accelerometer means; a vertical displacement sensor; and an optimal filter means for integrating electronic outputs from said gravity gradiometer means, said three axis inertial position determining means and said vertical displacement sensor.
Claim 3
Dependent Claim
33 words
A navigation system as defined in claim 1 wherein said gravity gradiometer means measures less than every element of the complete local gravity gradient tensor and produces estimates of the local gravity field.
Claim 4
Dependent Claim
52 words
A navigation system as defined in claim 1 wherein said gravity gradiometer means comprises: a plurality of accelerometers mounted on a rotatable support mounting means; means for rotating said rotatable support mounting means; and a housing for said means for rotating and said rotatable support mounting means supported by a stabilized platform.
Claim 5
Dependent Claim
56 words
A navigation system as defined in claim 3 wherein said gravity gradiometer means comprises: a shake accelerometer oriented along the axis of said rotatable support mounting means and mechanically coupled thereto; a shake actuator mechanically coupled to said shake accelerometer; and spring bias means for supporting said shake actuator and said shake accelerometer within said housing.
Claim 6
Dependent Claim
16 words
A navigation system as defined in claim 3 wherein said plurality of accelerometers comprises four accelerometer.
Claim 7
Dependent Claim
27 words
A navigation system as defined in claim 3 wherein said plurality of accelerometers are mounted tangentially and equally spaced apart radially on said rotatable support mounting means.
Claim 8
Dependent Claim
20 words
A navigation system as defined in claim 1 wherein said gravity gradiometer means comprises one to three rotating gravity gradiometers.
Claim 9
Dependent Claim
16 words
A navigation system as defined in claim 1 adapted to function as a gravity survey system.
Claim 10
Dependent Claim
31 words
A navigation system as defined in claim 1 wherein said gravity gradiometer means measures every element of the complete local gravity gradient tensor and produces estimates of the local gravity field.
Claim 11
Dependent Claim
66 words
A navigation system, comprising: a gradiometer means comprising from one to three gradiometers each comprising four rotating accelerometers mounted tangentially at cardinal points on a rotating means; a three axis inertial position determining means including a gravimeter grade vertical accelerometer; a depth sensor; and an optimal filter means for integrating outputs from said gradiometer means; said three axis inertial position determining means and said depth sensor.
Claim 12
Dependent Claim
66 words
A navigation system, comprising: a gradiometer means comprising from one to three gradiometers each comprising four rotating accelerometers mounted tangentially at cardinal points on a rotating means; a three axis inertial position determining means including a gravimeter grade vertical accelerometer; a depth sensor; and an optimal filter means for integrating outputs from said gradiometer means; said three axis inertial position determining means and said depth sensor.
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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) | 1997-08-22 | 1998-02-21 | 1998-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-08-22 | 2002-02-21 | 2002-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-08-22 | 2006-02-21 | 2006-08-23 | $7700.00 | Window Closed / Lapsed |