Azimuth meter
First Claim
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1. An azimuth meter, comprising:
- a plane coil wound into a shape symmetrical with respect to two axes perpendicular to each other; and
at least of groups of thin film magneto resistive elements disposed substantially parallel to the plane oft plane coil, in which each of said groups of magneto resistive elements constitutes an MR bridge of an even number of magneto resistive elements electrically connected to each other and detects and outputs two perpendicular components of the earth magnetism, and bearing information is obtained based on the output values, wherein the azimuth meter further comprises;
means of passing a current in a predetermined direction through the plane coil to apply thereto a magnetic field that is equal to or higher than a saturation magnetization of said magneto resistive elements, applying a constant biasing magnetic field in the opposite direction, applying a magnetic field equal to or higher than the saturation magnetization of the magneto resistive elements in the direction opposite to said predetermined direction, and then applying a biasing magnetic field in the opposite direction; and
means of passing a magnetic field measuring current through the groups of the thin film magneto resistive elements concurrently with the applications of said biasing magnetic fields.
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Abstract
To provide a thin and small area azimuth meter. A plane coil and at least two groups of thin film magneto resistive elements are arranged. Each of the groups of thin film magneto resistive elements constitutes an MR bridge and detects and outputs two perpendicular components of the earth magnetism, and bearing information is obtained based on the output values.
24 Citations
8 Claims
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1. An azimuth meter, comprising:
- a plane coil wound into a shape symmetrical with respect to two axes perpendicular to each other; and
at least of groups of thin film magneto resistive elements disposed substantially parallel to the plane oft plane coil, in which each of said groups of magneto resistive elements constitutes an MR bridge of an even number of magneto resistive elements electrically connected to each other and detects and outputs two perpendicular components of the earth magnetism, and bearing information is obtained based on the output values, wherein the azimuth meter further comprises;
means of passing a current in a predetermined direction through the plane coil to apply thereto a magnetic field that is equal to or higher than a saturation magnetization of said magneto resistive elements, applying a constant biasing magnetic field in the opposite direction, applying a magnetic field equal to or higher than the saturation magnetization of the magneto resistive elements in the direction opposite to said predetermined direction, and then applying a biasing magnetic field in the opposite direction; and
means of passing a magnetic field measuring current through the groups of the thin film magneto resistive elements concurrently with the applications of said biasing magnetic fields. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- a plane coil wound into a shape symmetrical with respect to two axes perpendicular to each other; and
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8. A method for obtaining bearing information comprising:
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providing an azimuth meter which comprises;
a plane coil wound into a shape symmetrical with respect to two axes perpendicular to each other; and
at least two groups of thin film magneto resistive elements disposed substantially parallel to the plane of the plane coil, in which each of said groups of magneto resistive elements constitutes an MR bridge of an even number of magneto resistive elements electrically connected to each other and detects and outputs two perpendicular components of earth magnetism, with bearing information being obtained based on output values therefrom;
wherein said azimuth meter further comprises;
means of passing a current in a predetermined direction through said plane coil to apply thereto a magnetic field that is equal to or higher than a saturation magnetization of said magneto resistive elements;
applying a constant biasing magnetic field in the opposite direction;
applying a magnetic field equal to or higher than said saturation magnetization of said magneto resistive elements in a direction opposite to said predetermined direction, and then applying a biasing magnetic field in said opposite direction;
means for passing a magnetic field measuring current through said groups of the thin film magneto resistive elements concurrently with said applications of said biasing magnetic fields, passing said magnetic field measuring current through the plane coil in said predetermined direction to apply to said groups of thin film magneto resistive elements said magnetic field that is equal to or higher than said saturation magnetization of said magneto resistive elements;
applying to said groups of thin film magnetic resistive elements said constant biasing magnetic field in said opposite direction, while passing said magnetic field measuring current through said groups of thin film magneto resistive elements to measure a resulting magnetic field and to obtain an output value from said groups of thin film magneto resistive elements;
applying to said groups of thin film magneto resistive elements said magnetic field equal to or higher than said saturation magnetization of said magneto resistive elements in said direction opposite to said predetermined direction, applying to said groups of thin film magneto resistive elements said biasing magnetic field in said direction opposite to said direction of said magnetic field applied immediately before, which magnetic field applied immediately before is said magnetic field which is equal to or higher than said saturation magnetization of said magneto restrictive elements while passing said magnetic field measuring current through said groups of thin film magneto resistive elements to measure said resulting magnetic field and to obtain an output value from said groups of thin film magneto resistive elements, and obtaining bearing information on said output values.
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Specification