US4429469A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Direction detection apparatus
Assignee: Alps Alpine Co Ltd
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Filing: 1981-11-12
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Granted: 1984-02-07
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Expires: 2001-11-12
Abstract
Abstract A direction detection apparatus comprising a magnetic sensor which senses a geomagnetic azimuth, a turning-angle sensor which senses a turning angle dynamically, a magnetic-disturbance detector which detects a magnetic disturbance on the basis of the output of the magnetic sensor, and a signal switching device which transmits either the magnetic sensor output or the turning-angle sensor output to a display device in accordance with a signal from the magnetic-disturbance detector. The traveling direction of a moving object can be detected as a precise geographic azimuth even when the moving object lies in a place subject to the magnetic disturbance.
Inventors
- 👤 Noboru Tsushima
- 👤 Makoto Tomoyori
- 👤 Masatoshi Harumatsu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 03:13
CPC Classifications
G; G01; G01C; G01C17/00; G01C17/02; G01C17/28; G01C17/30
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
140 words
A direction detection apparatus for an automobile which includes a display means to show the direction of movement of the automobile, the direction apparatus further comprising a magnetic sensor means for sensing a geomagnetic azimuth and for producing an output signal in accordance with said azimuth, a turning-angle sensor means for dynamically sensing the turning angle of said automobile and producing an output signal in accordance with said turning angle, a magnetic-disturbance detector means for detecting a magnetic disturbance on the basis of the signal output of the said magnetic sensor means and producing a disturbance output signal upon said disturbance, and an automatic signal switching means for applying either the magnetic sensor means output signal or the turning-angle sensor means output signal to the said display device in accordance with said disturbance output signal from said magnetic-disturbance detector means.
Claim 2
Dependent Claim
140 words
A direction detection apparatus for an automobile which includes a display means to show the direction of movement of the automobile, the direction apparatus further comprising a magnetic sensor means for sensing a geomagnetic azimuth and for producing an output signal in accordance with said azimuth, a turning-angle sensor means for dynamically sensing the turning angle of said automobile and producing an output signal in accordance with said turning angle, a magnetic-disturbance detector means for detecting a magnetic disturbance on the basis of the signal output of the said magnetic sensor means and producing a disturbance output signal upon said disturbance, and an automatic signal switching means for applying either the magnetic sensor means output signal or the turning-angle sensor means output signal to the said display device in accordance with said disturbance output signal from said magnetic-disturbance detector means.
Claim 3
Dependent Claim
91 words
A direction detection apparatus according to claim 1, and further comprising: (a) means for comparing, at a sequence of fixed times, a resultant vector which is the product of a geomagnetism vector and a disturbing magnetism vector, with the immediately preceding resultant vector; and, when said magnetic disturbance has been detected by the said comparing means, (b) means for calculating the output of said turning-angle sensor to obtain a correct geographic azimuth by reference to the correct azimuth information which existed immediately before the magnetic disturbance detected by said magnetic sensor.
Claim 4
Dependent Claim
53 words
A direction detection apparatus according to claim 2, wherein when the absence of the magnetic disturbance has been detected by said comparing means in obtaining a geographic information based on the output of said turning-angle sensor means, the input azimuth information to said azimuth display device is again obtained from said magnetic sensor.
Claim 5
Dependent Claim
34 words
A direction detection apparatus according to claim 1, including means to correct a magnetic deviation so as to correct the azimuth information from said magnetic sensor means and thereby provide a correct geographic azimuth.
Claim 6
Dependent Claim
23 words
A direction detection apparatus according to claim 1, wherein said magnetic sensor means includes a flux-gate magnetic sensor head employing a toroidal core.
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) | 1987-02-06 | 1987-08-08 | 1988-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-06 | 1991-08-08 | 1992-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-06 | 1995-08-08 | 1996-02-07 | $7700.00 | Window Closed / Lapsed |