US6418376B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus to maintain compass heading with a moveable sensor mounting
Assignee: Visteon Global Technologies Inc
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Filing: 2000-08-30
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Granted: 2002-07-09
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Expires: 2020-08-30
Abstract
Abstract An electronic compass system for use in an adjustable fixture in a vehicle such as an automobile including a sensor for detecting a magnetic field and for providing electrical signals representative of the direction of the vehicle with respect to the magnetic field. Relative position sensors provide electronic compass orientation relative to the vehicle. A circuit coupled to said sensing means resolve the direction and relative position electrical signals into a number of data points from which the detected direction of the vehicle may be calculated. The circuit also provides heading output signals representing heading information corresponding to the detected direction. An indicator coupled to the circuit provides an indication of the vehicle heading in response to said heading output signals, where the circuit includes a processor responsive to the direction electrical signals for determining a relative field strength of the magnetic field, for varying the resolution at which the circuit resolves the direction electrical signals into heading information as a function of the detected strength of the magnetic field, and for recalibrating the heading signal in response to sensor orientation signals to maintain accuracy of the indicated heading information. The processing means varies the resolution by adjusting the number of data points into which said direction representative electrical signals can be resolved.
Inventors
- 👤 Thomas R. Olson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:32
CPC Classifications
G; G01; G01C; G01C17/00; G01C17/02; G01C17/28; G01C17/30
Claims Analysis
Total Claims: 42
Claim 1
Independent Claim
142 words
A compass system, comprising: a housing, the housing supporting a compass unit; a position sensor, the position sensor determining displacement of the housing with respect to a generally horizontal plane, the sensor generating a displacement signal; a magnetic sensor, the magnetic sensor determining an orientation of the housing with respect to a magnetic field, the magnetic sensor generating a magnetic field signal; a compensation controller, the compensation controller varying the magnetic field signal by an offset; and an offset update circuit, the offset update circuit receiving the displacement signal and compensating for displacement of the housing by determining a first average magnetic field signal and comparing the first average magnetic field signal with a second average magnetic field signal generated prior to the first average magnetic field signal to define a difference signal, the difference signal being used to determine the offset.
Claim 2
Dependent Claim
142 words
A compass system, comprising: a housing, the housing supporting a compass unit; a position sensor, the position sensor determining displacement of the housing with respect to a generally horizontal plane, the sensor generating a displacement signal; a magnetic sensor, the magnetic sensor determining an orientation of the housing with respect to a magnetic field, the magnetic sensor generating a magnetic field signal; a compensation controller, the compensation controller varying the magnetic field signal by an offset; and an offset update circuit, the offset update circuit receiving the displacement signal and compensating for displacement of the housing by determining a first average magnetic field signal and comparing the first average magnetic field signal with a second average magnetic field signal generated prior to the first average magnetic field signal to define a difference signal, the difference signal being used to determine the offset.
Claim 3
Dependent Claim
15 words
The compass system of claim 1 wherein the position sensor is an optically triggered sensor.
Claim 4
Dependent Claim
32 words
The compass system of claim 1 further comprising a rotation sensor, the rotation sensor generating a rotation signal which varies in accordance with rotation of the housing about a generally vertical axis.
Claim 5
Dependent Claim
34 words
The compass system of claim 3 wherein the offset update circuit further includes a rotational update circuit receiving the rotation signal and determining a rotational offset, the rotational offset in part determining the offset.
Claim 6
Dependent Claim
28 words
The compass system of claim 3 wherein the position sensor and the rotation sensor are integral to form a composite sensor, and the composite sensor is optically triggered.
Claim 7
Dependent Claim
25 words
The compass system of claim 1 wherein the magnetic sensor determines the orientation of the housing with respect to the magnetic field of the earth.
Claim 8
Dependent Claim
55 words
The compass system of claim 1 wherein the magnetic sensor further comprises: a first magnetic sensor for determining orientation of the compass unit with respect to a first magnetic axis; and a second magnetic sensor for determining orientation of the compass unit with respect to a second magnetic axis orthogonal to the first magnetic axis.
Claim 9
Dependent Claim
17 words
The compass system of claim 7 wherein the magnetic field is the magnetic field of the earth.
Claim 10
Dependent Claim
31 words
The compass system of claim 7 wherein the first axis is one of a north/south and east/west axis, and the second axis is the other of the north/south and east/west axis.
Claim 11
Dependent Claim
200 words
A compass system, comprising: a housing, the housing supporting a compass unit; a position sensor, the position sensor determining displacement of the housing with respect to a generally horizontal plane, the sensor generating a displacement signal; a first magnetic sensor for determining orientation of the compass unit with respect to a first magnetic axis, the first magnetic sensor generating a first magnetic field signal; a second magnetic sensor for determining orientation of the compass unit with respect to a second magnetic axis orthogonal to the first magnetic axis, the second magnetic sensor generating a second magnetic field signal, wherein the first and second magnetic field signals are combined to define a composite magnetic field signal; a compensation controller, the compensation controller varying the composite magnetic field signal by an offset; and an offset update circuit, the offset update circuit receiving the displacement signal and compensating for displacement of the housing by determining a first average composite magnetic field signal and comparing the first average composite magnetic field signal with a second average composite magnetic field signal determined prior to the first average composite magnetic field signal to define a difference signal, the difference signal being used to determine the offset.
Claim 12
Dependent Claim
200 words
A compass system, comprising: a housing, the housing supporting a compass unit; a position sensor, the position sensor determining displacement of the housing with respect to a generally horizontal plane, the sensor generating a displacement signal; a first magnetic sensor for determining orientation of the compass unit with respect to a first magnetic axis, the first magnetic sensor generating a first magnetic field signal; a second magnetic sensor for determining orientation of the compass unit with respect to a second magnetic axis orthogonal to the first magnetic axis, the second magnetic sensor generating a second magnetic field signal, wherein the first and second magnetic field signals are combined to define a composite magnetic field signal; a compensation controller, the compensation controller varying the composite magnetic field signal by an offset; and an offset update circuit, the offset update circuit receiving the displacement signal and compensating for displacement of the housing by determining a first average composite magnetic field signal and comparing the first average composite magnetic field signal with a second average composite magnetic field signal determined prior to the first average composite magnetic field signal to define a difference signal, the difference signal being used to determine the offset.
Claim 13
Dependent Claim
15 words
The compass system of claim 10 wherein the position sensor is an optically triggered sensor.
Claim 14
Dependent Claim
32 words
The compass system of claim 10 further comprising a rotation sensor, the rotation sensor generating a rotation signal which varies in accordance with rotation of the housing about a generally vertical axis.
Claim 15
Dependent Claim
39 words
The compass system of claim 12 wherein the offset update circuit further includes a rotational update circuit receiving the rotation signal and determining a rotational offset angle, the rotational offset angle in part determining the orientation of the housing.
Claim 16
Dependent Claim
28 words
The compass system of claim 13 wherein the position sensor and the rotation sensor are integral to form a composite sensor, and the composite sensor is optically triggered.
Claim 17
Dependent Claim
28 words
The compass system of claim 12 wherein the first and second magnetic sensors determine the orientation of the housing with respect to the magnetic field of the earth.
Claim 18
Dependent Claim
31 words
The compass system of claim 15 wherein the first axis is one of a north/south and east/west axis, and the second axis is the other of the north/south and east/west axis.
Claim 19
Independent Claim
84 words
A method for compensating a compass mounted in a displaceable housing where displacement of the housing changes the orientation of the compass, comprising the step of: determining if the housing has been tilted with respect to a horizontal plane; determining a present magnetic orientation of the compass; comparing the present magnetic orientation with a previous magnetic orientation to determine a difference between the present and previous magnetic orientations and generating an offset value; and updating a calibration value in accordance with the offset values.
Claim 20
Independent Claim
84 words
A method for compensating a compass mounted in a displaceable housing where displacement of the housing changes the orientation of the compass, comprising the step of: determining if the housing has been tilted with respect to a horizontal plane; determining a present magnetic orientation of the compass; comparing the present magnetic orientation with a previous magnetic orientation to determine a difference between the present and previous magnetic orientations and generating an offset value; and updating a calibration value in accordance with the offset values.
Claim 21
Dependent Claim
57 words
The method of claim 17 further comprising the steps of: determining if the compass housing has been rotationally displaced with respect to a generally vertical axis; determining a rotational signal in accordance with an amount of rotation of the housing; and determining a rotational offset value compensating the magnetic heading in accordance with the rotational offset value.
Claim 22
Dependent Claim
103 words
A vehicle compass configured for mounting in an adjustable vehicle interior element comprising: a magnetic field sensor configured to sense the Earth's magnetic field and to generate orientation signals representative of the orientation of the magnetic field sensor with respect to the Earth's magnetic field; a position sensor configured to sense adjustments in the orientation of the magnetic field sensor as the vehicle interior element is adjusted and to generate position sensor signals; and a control circuit configured to receive the orientation signals and the position sensor signals and to generate heading signals based on the orientation signals and the position sensor signals.
Claim 23
Dependent Claim
103 words
A vehicle compass configured for mounting in an adjustable vehicle interior element comprising: a magnetic field sensor configured to sense the Earth's magnetic field and to generate orientation signals representative of the orientation of the magnetic field sensor with respect to the Earth's magnetic field; a position sensor configured to sense adjustments in the orientation of the magnetic field sensor as the vehicle interior element is adjusted and to generate position sensor signals; and a control circuit configured to receive the orientation signals and the position sensor signals and to generate heading signals based on the orientation signals and the position sensor signals.
Claim 24
Dependent Claim
21 words
The vehicle compass of claim 19 wherein the position sensor is configured to sense tilting adjustments of the magnetic field sensor.
Claim 25
Dependent Claim
21 words
The vehicle compass of claim 19 wherein the position sensor is configured to sense twisting adjustments of the magnetic field sensor.
Claim 26
Dependent Claim
22 words
The vehicle compass of claim 19 further comprising means for determining whether the position sensor signals are within a normal usage range.
Claim 27
Dependent Claim
18 words
The vehicle compass of claim 19 further comprising a reference table for use in generating the heading signals.
Claim 28
Dependent Claim
25 words
The vehicle compass of claim 19 wherein the position sensor is selected from a rotational potentiometer, an RVDT, an optical encoder, and an optical sensor.
Claim 29
Dependent Claim
19 words
The vehicle compass of claim 19 wherein the position sensor comprises a photodetector and at least one light source.
Claim 30
Dependent Claim
20 words
The vehicle compass of claim 19 wherein the position sensor is selected from a magneto-inductive sensor and a magneto-restrictive sensor.
Claim 31
Dependent Claim
25 words
The vehicle compass of claim 19 further comprising a display, wherein the display receives the heading signals and provides a display of the heading signals.
Claim 32
Dependent Claim
23 words
The vehicle compass of claim 19 wherein the position sensor is configured to sense adjustments in the position of an adjustable rearview mirror.
Claim 33
Independent Claim
53 words
A method for calibrating a compass system having a magnetic field sensor coupled to an adjustable vehicle interior element comprising: providing a magnetic field signal; providing a displacement signal based on a displacement of the magnetic field sensor; and calculating a heading signal based on the magnetic field signal and the displacement signal.
Claim 34
Independent Claim
53 words
A method for calibrating a compass system having a magnetic field sensor coupled to an adjustable vehicle interior element comprising: providing a magnetic field signal; providing a displacement signal based on a displacement of the magnetic field sensor; and calculating a heading signal based on the magnetic field signal and the displacement signal.
Claim 35
Dependent Claim
18 words
The method of claim 29 wherein the displacement signal represents a tilting adjustment of the magnetic field sensor.
Claim 36
Dependent Claim
52 words
The method of claim 30 wherein the step of calculating a heading signal comprises receiving the displacement signal, determining a first magnetic orientation of the magnetic field sensor, and comparing the first magnetic orientation with a second magnetic field orientation of the magnetic field sensor determined prior to the first magnetic orientation.
Claim 37
Dependent Claim
18 words
The method of claim 29 wherein the displacement signal represents a twisting adjustment of the magnetic field sensor.
Claim 38
Dependent Claim
27 words
The method of claim 32 wherein the step of calculating a heading signal comprises receiving the displacement signal and retrieving a heading offset from a reference table.
Claim 39
Dependent Claim
18 words
The method of claim 29 further comprising determining whether the displacement signal is within a normal usage range.
Claim 40
Dependent Claim
26 words
The method of claim 29 wherein the magnetic field signal is based on an orientation of the magnetic field sensor with respect to a magnetic field.
Claim 41
Dependent Claim
16 words
The method of claim 35 wherein the magnetic field is a magnetic field of the Earth.
Claim 42
Dependent Claim
11 words
The method of claim 29 further comprising displaying the heading signal.
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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) | 2005-07-08 | 2006-01-07 | 2006-07-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-07-08 | 2010-01-07 | 2010-07-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-07-08 | 2014-01-07 | 2014-07-09 | $7700.00 | Window Closed / Lapsed |