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US5265025A
Expired / Lapsed
US
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Navigation system using satellite signals
Assignee: Mitsubishi Electric Corp
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Filing: 1991-07-05
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Granted: 1993-11-23
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Expires: 2011-07-05
Abstract
Abstract The navigation system using GPS signals from satellites first checks whether or not there are four or more satellites in radio range of the moving body. If so, the position calculation section performs an ordinary three-dimensional positioning operation to provide an accurate fix of the moving body. When the number of satellites within the radio range is three or less, the two-dimensional positioning operation is carried out, which comprises reading the previous altitude data from the altitude storage section; calculating the atmospheric pressure deviation from the atmospheric pressure sensor output as caused by the movement of the body; calculating the altitude deviation from the previous altitude data and the atmospheric pressure deviation; calculating the current altitude from the altitude deviation and the previous altitude data; and then calculating the two-dimensional position data from the GPS signals and the current altitude data. This method produces no errors which would otherwise be caused by changes in the altitude of the moving body but provides accurate two-dimensional fix data of the body.
Inventors
- 👤 Seiichiro Hirata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:48
CPC Classifications
G; G01; G01S; G01S19/00; G01S19/38; G01S19/39; G01S19/42; G01S19/48; G01C; G01C21/00; G01C21/005; G01C21/26; G01C21/28; G01C5/00; G01C5/06; G01S19/01; G01S19/03; G01S19/10; G01S19/11; G01S19/13; G01S5/00; G01S5/01; G01S5/017; G01S5/018
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
182 words
A navigation system using satellite radio signals comprising: a GPS receiver station for receiving global positioning system (GPS) signals from a plurality satellites; decision means for determining if a number of the plurality of satellites in radio range of a moving body is four or more; an atmospheric pressure sensor for measuring atmospheric pressure at a location of the moving body; an altitude deviation calculating section for calculating an atmospheric pressure deviation produced by movement of the moving body from the measured atmospheric pressure and for determining an altitude deviation of the moving body from the calculated atmospheric pressure deviation; an altitude storage section for storing altitude data of the moving body; and position calculating means for calculating two-dimensional position data of the moving body from the GPS signals and altitude data based on the GPS signals when the number of the plurality of satellites is four or more and for calculating the two-dimensional position data of the moving body from the GPS signals, stored altitude data, and the altitude deviation when the number of plurality of satellites is three or less.
Claim 2
Dependent Claim
182 words
A navigation system using satellite radio signals comprising: a GPS receiver station for receiving global positioning system (GPS) signals from a plurality satellites; decision means for determining if a number of the plurality of satellites in radio range of a moving body is four or more; an atmospheric pressure sensor for measuring atmospheric pressure at a location of the moving body; an altitude deviation calculating section for calculating an atmospheric pressure deviation produced by movement of the moving body from the measured atmospheric pressure and for determining an altitude deviation of the moving body from the calculated atmospheric pressure deviation; an altitude storage section for storing altitude data of the moving body; and position calculating means for calculating two-dimensional position data of the moving body from the GPS signals and altitude data based on the GPS signals when the number of the plurality of satellites is four or more and for calculating the two-dimensional position data of the moving body from the GPS signals, stored altitude data, and the altitude deviation when the number of plurality of satellites is three or less.
Claim 3
Dependent Claim
124 words
A navigation system, comprising: GPS receiving means for receiving GPS signals, including altitude information, from a plurality of satellites; determining means for determining if a number of the plurality of satellites is greater than three; storing means for storing the altitude information; atmospheric pressure sensor means for measuring atmospheric pressure; and altitude deviation calculating means for calculating an altitude deviation from a deviation in the measure atmospheric pressure; position calculating means for calculating two-dimensional position data from the GPS signals, including the altitude information, when the number of satellites is greater than three and for calculating the two-dimensional position data from the GPS signals, the stored altitude information, and the altitude deviation when the number of satellites is less than or equal to three.
Claim 4
Dependent Claim
124 words
A navigation system, comprising: GPS receiving means for receiving GPS signals, including altitude information, from a plurality of satellites; determining means for determining if a number of the plurality of satellites is greater than three; storing means for storing the altitude information; atmospheric pressure sensor means for measuring atmospheric pressure; and altitude deviation calculating means for calculating an altitude deviation from a deviation in the measure atmospheric pressure; position calculating means for calculating two-dimensional position data from the GPS signals, including the altitude information, when the number of satellites is greater than three and for calculating the two-dimensional position data from the GPS signals, the stored altitude information, and the altitude deviation when the number of satellites is less than or equal to three.
Claim 5
Dependent Claim
22 words
The navigation system of claim 2, wherein the altitude deviation and the stored altitude information are added to produce current altitude information.
Claim 6
Dependent Claim
15 words
The navigation system of claim 3, wherein the stored altitude information is previous altitude information.
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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) | 1996-11-22 | 1997-05-24 | 1997-11-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-11-22 | 2001-05-24 | 2001-11-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-11-22 | 2005-05-24 | 2005-11-23 | $7700.00 | Window Closed / Lapsed |