Geomagnetic sensor and azimuth calculation method thereof
First Claim
1. A geomagnetic sensor, comprising:
- a geomagnetic measurement module including flux gates of X, Y and Z axes mutually crossing at right angles;
a tilt measurement module including acceleration sensors of X, Y and Z axes mutually crossing at right angles;
a tilt calculator primarily calculating a pitch angle and a roll angle using output values of each acceleration sensor of the X and Y axes, and performing second calculation by adjusting at least one of the primarily calculated pitch angle and roll angle using an output value of the acceleration sensor of the Z axis; and
a controller calculating an azimuth using the readjusted pitch angle and roll angle and an output value of the geomagnetic measurement module.
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Abstract
A geomagnetic sensor with 3-axis acceleration sensors is provided. The geomagnetic sensor a geomagnetic measurement module including flux gates of X, Y and Z axes mutually crossing at right angles, a tilt measurement module including acceleration sensors of X, Y and Z axes mutually crossing at right angles, a tilt calculator primarily calculating a pitch angle and a roll angle using output values of each acceleration sensors of the X and Y axes, and performing second calculation by adjusting at least one of the primarily calculated pitch angle and roll angle using an output value of the acceleration sensor of the Z axis, and a controller calculating an azimuth using the readjusted pitch angle and roll angle and an output value of the geomagnetic measurement module. Accordingly, the pitch angle and roll angle are precisely measured to calculate the azimuth.
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Citations
21 Claims
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1. A geomagnetic sensor, comprising:
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a geomagnetic measurement module including flux gates of X, Y and Z axes mutually crossing at right angles;
a tilt measurement module including acceleration sensors of X, Y and Z axes mutually crossing at right angles;
a tilt calculator primarily calculating a pitch angle and a roll angle using output values of each acceleration sensor of the X and Y axes, and performing second calculation by adjusting at least one of the primarily calculated pitch angle and roll angle using an output value of the acceleration sensor of the Z axis; and
a controller calculating an azimuth using the readjusted pitch angle and roll angle and an output value of the geomagnetic measurement module. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of calculating an azimuth, comprising:
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(a) calculating output values of flux gates of X, Y and Z axes using the flux gates of the X, Y and Z axes mutually crossing at right angles;
(b) primarily calculating a pitch angle and a roll angle using acceleration sensors of X, Y and Z axes mutually crossing at right angles;
(c) adjusting at least one of the primarily calculated pitch angle and roll angle using an output value of the acceleration sensor of the Z axis; and
(d) calculating the azimuth using the readjusted pitch angle and roll angle and an output value of a geomagnetic measurement module. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. At least one computer readable medium storing instructions that control at least one processor to perform a method of calculating an azimuth, comprising:
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(a) calculating output values of flux gates of X, Y and Z axes using the flux gates of the X, Y and Z axes mutually crossing at right angles;
(b) primarily calculating a pitch angle and a roll angle using acceleration sensors of X, Y and Z axes mutually crossing at right angles;
(c) adjusting at least one of the primarily calculated pitch angle and roll angle using an output value of the acceleration sensor of the Z axis; and
(d) calculating the azimuth using the readjusted pitch angle and roll angle and an output value of a geomagnetic measurement module. - View Dependent Claims (16, 17, 18, 19)
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20. At least one computer readable medium as recited in 16, wherein in the step of (a), the output values of each flux gate of the X, Y and Z axes are normalized into values of a preset range using the following equations:
where Xnorm, Ynorm and Znorm are the normalized output values of each flux gate of the X, Y and Z axes respectively, Xraw, Yraw and Zraw are the real output values of each flux gate of the X, Y and Z axes respectively, Xoffset, Yoffset and Zoffset are the preset offset values of each flux gate of the X, Y and Z axes respectively, and XScale, YScale and ZScale are the preset scale values of each flux gate of the X, Y and Z axes respectively.
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21. At least one computer readable medium as recited in 20, wherein in the step of (d), the azimuth is calculated by applying the normalized output values of each flux gate of the X, Y and Z and the readjusted pitch angle and roll angle to the following equation:
where Xnorm, Ynorm and Znorm are the normalized output values of each flux gate of the X, Y and Z axes respectively, θ
is the pitch angle, and Φ
is the roll angle.
Specification