Calibration apparatus for automatic magnetic compass correction
First Claim
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1. Apparatus for providing a deviation-corrected output signal representative of an actual compass heading comprising:
- a magnetic compass providing an output signal representative of an indicated compass heading;
means for storing deviation-correction signals representative of the deviation of the compass for each of a plurality of different indicated headings;
means for retrieving the stored deviation-correction signal corresponding with the indicated compass heading in response to the output signal from the compass;
means responsive to the retrieved deviation-correction signal and to the compass output signal for producing a deviation-corrected output signal representative of the actual compass heading; and
a calibration circuit, includingmeans for providing signals representative of the actual heading of the compass;
means for providing the compass output signal to the calibration circuit;
means responsive to the signals representative of the actual heading and to the compass output signal for providing signals representative of the difference therebetween; and
means for causing the difference signals to be stored by the storing means.
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Abstract
Method and apparatus for providing calibration of automatic deviation-correction circuitry for a magnetic compass. Data representing deviation-corrections for respective compass headings are derived by comparing signals representative of the actual heading of the compass with the compass output signal at a plurality of headings to provide corresponding corrections which are stored in a memory to produce an output signal representing actual heading and corrected for deviation error.
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Citations
9 Claims
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1. Apparatus for providing a deviation-corrected output signal representative of an actual compass heading comprising:
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a magnetic compass providing an output signal representative of an indicated compass heading; means for storing deviation-correction signals representative of the deviation of the compass for each of a plurality of different indicated headings; means for retrieving the stored deviation-correction signal corresponding with the indicated compass heading in response to the output signal from the compass; means responsive to the retrieved deviation-correction signal and to the compass output signal for producing a deviation-corrected output signal representative of the actual compass heading; and a calibration circuit, including means for providing signals representative of the actual heading of the compass; means for providing the compass output signal to the calibration circuit; means responsive to the signals representative of the actual heading and to the compass output signal for providing signals representative of the difference therebetween; and means for causing the difference signals to be stored by the storing means. - View Dependent Claims (2, 3, 4, 5)
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6. For use with a deviation-corrected magnetic compass of the type having a magnetic compass providing an output signal representative of an indicated compass heading and means for storing deviation-correction signals representative of the deviation of the compass for each of a plurality of different indicated headings and for producing a deviation-corrected signal corresponding with the indicated compass heading in response to the output signal from the compass;
a calibration circuit, comprising; means for providing signals representative of the actual heading of the compass; means for providing the compass output to the calibration circuit; means responsive to the signals representative of the actual heading and to the compass output signal for providing deviation-correction signals representative of the deviation of the indicated compass heading; and means for causing storage of the deviation-correction signals in the storing means. - View Dependent Claims (7, 9)
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8. A method for providing deviation-correction signals for a magnetic compass, comprising the steps of:
storing deviation-correction signals representative of the deviation of the compass for each of a plurality of different headings, by; rotating the compass through 360°
while the following steps are performed;providing signals representative of the actual heading of the compass; comparing the signals representative of the actual compass heading with the compass output signals to produce signals representative of the compass deviation; and storing deviation-correction signals representative of the deviation of the compass for each of a plurality of different headings; providing a digital compass output signal from a compass representative of an indicated compass heading; and retrieving in response to the output signal from the compass the stored deviation-correction signal corresponding with the indicated compass heading to produce a deviation-corrected output signal representative of the actual compass heading.
Specification