High resolution compass card position decoder
First Claim
1. A high resolution compass card position decoder comprising:
- a compass having a card mounted for rotation within said compass about an axis perpendicular to said card through the center of said card, said compass card having an inner digital encoding pattern and an outer peripheral pattern arranged with respect to the center of said card, said outer peripheral pattern including a series of lines each running at an angle to a radius of said card from an inner circular position to an outer circular position;
means along a first predetermined card radius for decoding the angular position of said card from said digital encoding pattern so as to decode gross compass heading; and
means along a second predetermined card radius for detecting the position along said second radius of one of said lines so as to decode fine compass heading.
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Accused Products
Abstract
The angular position of a compass card or like rotary encoder disk includes the utilization of an optical pickoff system in which the accuracy associated with a digitally encoded disk is enhanced through the utilization of a secondary analog optical pickoff system in which the outer periphery or border of the disk carrying the digital code is provided with a series of skewed lines running at an angle to the radius of the disk. A mask having a narrow slot is located to one side of the disk along the radius of the disk. A light source is positioned on the other side of the disk, and a linear array of detectors is positioned above the slot. The use of the skewed lines and slot amplifies the motion of the rotary encoder disk such that fine angular orientation may be detected by virtue of the position along the length of the slot of a line within the slot aperture.
55 Citations
29 Claims
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1. A high resolution compass card position decoder comprising:
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a compass having a card mounted for rotation within said compass about an axis perpendicular to said card through the center of said card, said compass card having an inner digital encoding pattern and an outer peripheral pattern arranged with respect to the center of said card, said outer peripheral pattern including a series of lines each running at an angle to a radius of said card from an inner circular position to an outer circular position; means along a first predetermined card radius for decoding the angular position of said card from said digital encoding pattern so as to decode gross compass heading; and means along a second predetermined card radius for detecting the position along said second radius of one of said lines so as to decode fine compass heading. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. Apparatus for determining the angular position of a shaft comprising:
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a disk mounted at its center to said shaft, said disk having an inner pattern including a single inner spiral running 360°
from a first circular position to a second circular position, and an outer peripheral pattern including a series of lines each running at an angle to the radius of said disk from a third circular position to a fourth circular position;means along a first predetermined disk radius for detecting the position along said first radius of said single inner spiral so as to decode gross angular position; and means along a second predetermined disk radius for detecting the position along said second radius of one of said lines so as to decode fine angular position. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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20. Apparatus for detecting the angular position of a shaft comprising:
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a disk mounted at is center to said shaft, said disk having an inner digital encoding pattern and an outer peripheral pattern, said outer peripheral pattern including a series of lines each running at an angle to a radius of said disk from an inner circular position to an outer circular position; means along a first predetermined disk radius for decoding the angular position of said disk from said digital encoding pattern so as to decode gross angular position; and means along a second predetermined disk radius for detecting the position along said second radius of one of said lines so as to decode fine angular position. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29)
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Specification