US4881080A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for and a method of determining compass headings
Assignee: United States Department of the Navy
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Filing: 1985-06-24
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Granted: 1989-11-14
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Expires: 2005-06-24
Abstract
Abstract A compass system and method incorporating a global positioning system (GP such as the NAVSTAR/GPS multi-satellite system, is configured to acquire accurate compass heading information without being affected by magnetic anomalies and without being dependent on the elapsed time since a previous position fix. The compass system comprises, inter alia, two antenna/preamplifiers located, for example, fore and aft a ship or aircraft separated by a predetermined distance d. A microprocessor/minicomputer portion of the system causes an electronic coaxial switch to switch a GPS receiver between the two antenna/preamplifiers automatically thereby measuring their absolute positions. The microprocessor/minicomputer computes and displays on a display unit a compass heading based on the knowledge of the absolute positions of the antenna/preamplifiers and the distance d therebetween.
Inventors
- 👤 Daniel G. Jablonski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 03:05
CPC Classifications
G; G01; G01S; G01S3/00; G01S3/02; G01S3/14; G01C; G01C17/00; G01C17/38
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
141 words
An improved method of determining compass headings of a platform (ship or aircraft) in association with the NAVSTAR/GPS multi-satellite system, said improved method comprising the steps of: positioning first and second antenna/preamplifiers fore and aft on paid platform a predetermined distance d apart in line with the heading of said platform; receiving position derivable data from said NAVSTAR/GPS multisatellite system via said first and second antenna/preamplifiers; reading the position fix of said first antenna/preamplifier from a GPS receiver into a microprocessor/minicomputer; switching said GPS receiver to said second antenna/preamplifier; reading the position fix of said second antenna/preamplifier from said GPS receiver into said microprocessor/minicomputer; and computing an equivalent compass heading in said microprocessor/minicomputer according to a predetermined equation based on the position fixes of said first and second antenna/preamplifiers as determined by said GPS receiver and the predetermined distance d therebetween.
Claim 2
Dependent Claim
141 words
An improved method of determining compass headings of a platform (ship or aircraft) in association with the NAVSTAR/GPS multi-satellite system, said improved method comprising the steps of: positioning first and second antenna/preamplifiers fore and aft on paid platform a predetermined distance d apart in line with the heading of said platform; receiving position derivable data from said NAVSTAR/GPS multisatellite system via said first and second antenna/preamplifiers; reading the position fix of said first antenna/preamplifier from a GPS receiver into a microprocessor/minicomputer; switching said GPS receiver to said second antenna/preamplifier; reading the position fix of said second antenna/preamplifier from said GPS receiver into said microprocessor/minicomputer; and computing an equivalent compass heading in said microprocessor/minicomputer according to a predetermined equation based on the position fixes of said first and second antenna/preamplifiers as determined by said GPS receiver and the predetermined distance d therebetween.
Claim 3
Dependent Claim
70 words
The improved method of claim 1 comprising the addition steps of: interrupting said GPS receiver after a predetermined waiting period starting after the reading of the position fix of said first antenna/preamplifier but ending before the reading of the position fix of said second antenna/preamplifier by said microprocessor/minicomputer; and estimating by said microprocessor/minicomputer a position fix for said second antenna/preamplifier based on the previously read position fix of first antenna/preamplifier.
Claim 4
Dependent Claim
48 words
The improved method of claim 2 wherein a correction, taking into account the predetermined distance d between said first and second antennas, is made to the estimated position fix of second antenna/preamplifier if a previous estimate for the compass heading of the platform is available in said microprocessor/minicomputer.
Claim 5
Dependent Claim
57 words
The improved method of claim 3 wherein the predetermined equation used in the computing step is: (X2-X1).sup.2 +(Y2-Y1).sup.2 +(Z2-Z1).sup.2 =d.sup.2, where X1, Y1, Z1 and X2, Y2, Z2 are the position fixes of said first and second antenna/preamplifiers respectively, as determined by said GPS receiver, and d is the predetermined distance between said first and second antenna/preamplifiers.
Claim 6
Dependent Claim
58 words
The improved method of claim 4 comprising the additional step of switching said GPS receiver to said first antenna/preamplifier, and repeating reading the position fix of said first antenna/preamplifier, switching said GPS receiver to said second antenna/preamplifier, reading the position fix of said second antenna/preamplifier, and computing an equivalent compass heading, thereby providing a continuously updated compass heading.
Claim 7
Dependent Claim
144 words
Apparatus determining compass headings of a platform (ship or aircraft) in association with the NAVSTAR/GPS multi-satellite system comprising: means for positioning first and second antenna/preamplifiers fore and aft on said platform a predetermined distance d apart in line with the heading of said platform; means for receiving position determinable data from said NAVSTAR/GPS multi-satellite system via said first and second antenna/preamplifiers; means for reading the position fix of said first antenna/preamplifier from a GPS receiver into a microprocessor/minicomputer; means for switching said GPS receiver to said second antenna/preamplifier; means for reading the position fix of said second antenna/preamplifier from said GPS receiver into said microprocessor/minicomputer; and means for computing an equivalent compass heading in said microprocessor/minicomputer according to a predetermined equation based on the position fixes of said first and second antenna/preamplifiers as determined by said GPS receiver and the predetermined distance d therebetween.
Claim 8
Dependent Claim
144 words
Apparatus determining compass headings of a platform (ship or aircraft) in association with the NAVSTAR/GPS multi-satellite system comprising: means for positioning first and second antenna/preamplifiers fore and aft on said platform a predetermined distance d apart in line with the heading of said platform; means for receiving position determinable data from said NAVSTAR/GPS multi-satellite system via said first and second antenna/preamplifiers; means for reading the position fix of said first antenna/preamplifier from a GPS receiver into a microprocessor/minicomputer; means for switching said GPS receiver to said second antenna/preamplifier; means for reading the position fix of said second antenna/preamplifier from said GPS receiver into said microprocessor/minicomputer; and means for computing an equivalent compass heading in said microprocessor/minicomputer according to a predetermined equation based on the position fixes of said first and second antenna/preamplifiers as determined by said GPS receiver and the predetermined distance d therebetween.
Claim 9
Dependent Claim
70 words
The apparatus of claim 6 further comprising: means for interrupting said GPS receiver after a predetermined waiting period starting after the reading of the position fix of said first antenna/preamplifier but ending before the reading of the position fix of said second antenna/preamplifier by said microprocessor/minicomputer; and means for estimating by said microprocessor/minicomputer a position fix for said second antenna/preamplifier based on the previously read position fix of first antenna/preamplifier.
Claim 10
Dependent Claim
55 words
The apparatus of claim 7 wherein the predetermined equation used in the computing step is: (X2-X1).sup.2 +(Y2-Y1).sup.2 +(Z2-Z1).sup.2 =d.sup.2, where X1, Y1, Z1 and X2, Y2, Z2 are the position fixes of said first and second antenna/preamplifiers respectively, as determined by said GPS receiver, and is the predetermined distance between said first and second antenna/preamplifiers.
Claim 11
Dependent Claim
55 words
The apparatus of claim 8 further comprising means for switching said GPS receiver to said first antenna/preamplifier, repeatedly reading the position fix of said first antenna/preamplifier, switching said GPS receiver to said second antenna/preamplifier, reading the position fix of said second antenna/preamplifier and computing an equivalent compass heading, thereby providing a continuously updated compass heading.
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) | 1992-11-13 | 1993-05-15 | 1993-11-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-13 | 1997-05-15 | 1997-11-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-13 | 2001-05-15 | 2001-11-14 | $7700.00 | Window Closed / Lapsed |