Flux-gate sensor mounting and method
First Claim
1. In an electronic compass system, including a flux-gate sensor having first and second orthogonal sense coils, said electronic compass using the arctangent function to calculate headings and displaying n sectors having n boundaries separated by a fixed number of degrees, wherein said boundaries are offset with respect to actual magnetic directions, a method of orienting a flux-gate sensor relative to actual magnetic directions to minimize display jitter between the boundaries, said method comprising:
- (a) orienting the display with actual magnetic directions; and
(b) orienting the first and second sense coils along four of said boundaries.
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Abstract
A flux-gate sensor orientation method which minimizes display jitter in electronic compasses which employ an n-point display or which calculate headings using the arctangent method. The method entails orienting the flux-gate sensor in a direction of plus or minus ±360°/2n relative to actual magnetic direction, so that instability points occur at display point boundaries. The method of the present invention finds application in microprocessor-based electronic compass systems but also makes possible the construction of a simple electronic compass employing small scale integration logic instead of a microprocessor.
22 Citations
12 Claims
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1. In an electronic compass system, including a flux-gate sensor having first and second orthogonal sense coils, said electronic compass using the arctangent function to calculate headings and displaying n sectors having n boundaries separated by a fixed number of degrees, wherein said boundaries are offset with respect to actual magnetic directions, a method of orienting a flux-gate sensor relative to actual magnetic directions to minimize display jitter between the boundaries, said method comprising:
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(a) orienting the display with actual magnetic directions; and (b) orienting the first and second sense coils along four of said boundaries. - View Dependent Claims (2, 3, 4)
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5. An electronic compass system for use in areas far enough from ferrous metals so as to be unaffected by the magnetic fields associated with such metals, comprising:
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(a) a flux-gate sensor having perpendicular first and second sense coils, each said sense coil being operable to generate a signal thereacross; (b) first circuit means for conditioning and processing the signal across the first sense coil and for producing a first direct current output signal; (c) second circuit means for conditioning and processing the signal across the second sense coil and for producing a second direct current output signal; (d) logic means, coupled to said first and second circuit means and having an output for determining compass heading using said first and second direct current output signals; (e) display interface means coupled to said logic means for converting the output of said logic means to a signal for display; and (f) display means coupled to said display interface means for displaying compass headings, said display means being divided into n sectors having n boundaries separated by a fixed number of degrees, wherein said boundaries are offset with respect to actual magnetic directions; said first and second sense coils being oriented along four of said sector boundaries. - View Dependent Claims (6, 7, 8, 9, 10, 11)
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12. An electronic compass system for determining vehicle headings comprising:
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(a) a flux-gate sensor, having first and second orthogonal sense coils, said flux-gate sensor being oriented plus or minus ±
360°
/2n relative to actual magnetic directions;(b) signal processing means coupled to said flux-gate sensor for generating first and second output signals having information about the heading of the vehicle; and (c) logic means responsive to said signal processing means for determining vehicle headings.
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Specification