JP2000131068A - Electronic declinometer and its correction value calculation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make easily and accurately performable the correction of a detection output value by the magnetization or the like of a declinometer and the adjustment for setting the maximum and minimum values of each component by a geomagnetism detection means. SOLUTION: The electronic declinometer and its correction value calculation method are provided with a geomagnetism detection means 10 for detecting the geomagnetism with two orthogonal components, a storage means 14 for storing an output value that is outputted from the geomagnetism detection means 10 when it is directed in mutually orthogonal, arbitrary three directions on a horizontal plane, an elliptical equation operation means 13 for obtaining the equation of an output elliptical locus when a declinometer is rotated by one turn from the storage means 14, an azimuth operation device 15 for obtaining the azimuth angle by correcting an output value that is detected by the geomagnetism detection means 10 according to a correction value that is obtained by the elliptical equation operation means 13, and a display device 4 for displaying an azimuth that is obtained by the azimuth operation device 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic azimuth meter capable of accurately recognizing an azimuth by detecting terrestrial magnetism and a method of calculating a correction value thereof.

[0002]

2. Description of the Related Art Conventionally, a terrestrial magnetism detecting means for detecting terrestrial magnetism has been provided, and an output corresponding to the strength of two orthogonal components has been obtained from the terrestrial magnetism detecting means. There is an electronic compass to calculate.

[0003] However, it has long been known that the above-mentioned electronic compass has hindered the function of the compass that measures an accurate geomagnetic direction due to the fact that electronic components and cases take on magnetic components other than geomagnetism. I was

That is, two axes orthogonal to each other (X axis, Y axis)
When the geomagnetic detection means with
For example, assuming that the angle between the X axis and the geomagnetic vector is θ, the magnetization amount m in the X axis direction and the magnetization amount n in the Y axis direction of the compass are added. When this is expressed in an equation, the equations (1) and (2) are obtained. Vx = Rx · cos θ + m (1) Vy = Ry · sin θ + n (2) (where Rx and Ry are proportional constants)

That is, assuming that the compass that has been magnetized in uniform geomagnetism makes one rotation, a perfect circle is drawn as shown in FIG. At this time, the center coordinates of the circle are (m, n).

Therefore, conventionally, a method has been used in which the amount of magnetization possessed by the compass is obtained by obtaining the center coordinates of a circle, and the above-mentioned amount of magnetization is corrected by calculation to obtain the azimuth.

A method for correcting magnetization of an electronic compass that has been filed in the past has been disclosed in Japanese Patent Application No. 4-151565 as an example. That is, while the electronic compass itself keeps its horizontal position, it makes one rotation, and in all directions, the detection outputs in the two mutually orthogonal magnetic detection directions are obtained, and the maximum values of these detection outputs are Xmax and Ymax for X and Y, respectively.
Assuming that x and the minimum value are Xmin and Ymin, there is a means for obtaining a correction value by m = (Xmax + Xmin) / 2 n = (Ymax + Ymin) / 2.

In Japanese Patent Application No. 5-95405, which describes a correction method which has been separately filed, an electronic compass is used to detect a detected output value in two mutually perpendicular magnetic detection directions in a predetermined direction. X1, Y1), and their arithmetic mean m = (X1 + X2) / 2 n = (Y1 + Y2) / 2 for output values (X2, Y2) in directions opposite to 180 ° while being kept horizontal from that direction. There was a means to correct by obtaining

The azimuth angle θ can be obtained by the equation (3) based on the correction value obtained as described above. θ = arctan ((Vy−n) / (Vx−m)) (3) (provided that α is obtained in advance so that Rx = α · Ry)

[0010]

However, in the above-described correction means, every time the user seems to have magnetized the compass, the measurement is performed while rotating the device once, and the above-mentioned correction means is used. It is necessary to update and store the maximum detection output of the two magnetic detection directions.Especially, the work is troublesome because one rotation is performed while keeping the device horizontal, and during that time the detection circuit continues to operate, so the power during this time is higher than usual It was consumed a lot and was unsuitable for portable devices.

In the above-described correction method, the center coordinates of the azimuth circle can be obtained. On the other hand, it is impossible to calculate the maximum detection output in the two magnetic detection directions. There was a drawback that it was not possible.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been made in consideration of the correction of a detection output value by magnetizing a compass, and the maximum and minimum values of each component of a terrestrial magnetism detecting means. It is an object of the present invention to provide an electronic azimuth meter capable of performing an adjustment for making the same the same easily and accurately, and a method of calculating a correction value thereof.

[0013]

In order to achieve the above object, an electronic compass of the present invention comprises: a geomagnetism detecting means for detecting geomagnetism by two components orthogonal to each other; Storage means for storing output values output from the terrestrial magnetism detection means in three directions, and elliptic equation calculation means for obtaining an equation of an output ellipse trajectory when the compass is rotated once from the storage means. An azimuth calculating device for obtaining an azimuth angle by correcting an output value detected by the terrestrial magnetism detecting device from a correction value obtained by the elliptic equation calculating device; and a display device for displaying the azimuth obtained by the azimuth calculating device. It is characterized by having.

In the method of calculating a correction value of an electronic compass according to the present invention, a geomagnetism detecting means for detecting geomagnetism with two components orthogonal to each other, and an arbitrary three orthogonal components on a horizontal plane.
The output value output from the terrestrial magnetism detection means when directed in the direction is stored in each storage means, and the elliptic equation is obtained from the output signals from the terrestrial magnetism detection means when directed in any of the three directions. Calculating the center coordinate of the ellipse and the maximum and minimum values of each of the two axes orthogonal to each other from the equation of the ellipse, and correcting the two output values detected by the geomagnetic detection means from the center coordinates and the maximum and minimum values of the ellipse. Features.

[Operation] By obtaining output values in three arbitrary directions orthogonal to each other on the horizontal plane by the geomagnetic detection means, an elliptic equation through which three coordinates pass can be obtained. And the amplitude for each of the two axes can be obtained.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments shown in the drawings. FIG. 1 is a diagram showing an electronic compass in an embodiment of the present invention. FIG. 2 is a block diagram illustrating an example of a circuit configuration according to the embodiment of the present invention. FIG. 3 is a diagram illustrating an example of a correction operation procedure according to the embodiment of the present invention. FIG. 4 is a diagram showing an oval diagram and a correction value obtained when a correction operation is performed in the embodiment of the present invention. FIG. 6 is a flowchart illustrating a correction operation procedure and a correction process according to the embodiment of the present invention. FIG. 7 is a flowchart illustrating an operation of calculating a correction value by calculation in the embodiment of the present invention. FIG. 8 is a flowchart showing the operation of calculating and displaying the azimuth in the embodiment of the present invention.

FIG. 1 is a schematic plan view of an electronic compass according to the present invention. In a case 1, a direction display switch 2, a correction switch 3, and a display are shown. A device 4 is provided.

The azimuth display switch 2 is a switch for starting azimuth measurement, and can obtain an azimuth angle or the like after predetermined processing. The correction switch 3 is a switch for operating the correction value calculation device of the present invention,
By operating the main body when the main body is oriented in a predetermined direction, a predetermined operation is performed and a correction value can be obtained. The display device 4 can display information such as an azimuth angle obtained by using a liquid crystal display device, for example.

[Description of Circuit Configuration: FIG. 2] As shown in FIG.
, A DC amplifier 11, an A / D converter 12, an azimuth display switch 2, a correction switch 3, a microcomputer 16, a storage means 14, and a display device 4. In the present embodiment, the microcomputer 16 can fulfill the same functions as those of the elliptic equation computing means 13 and the bearing computing device 15. Further, as the geomagnetism detecting means 10, for example, a flux gate type magnetic sensor can be used.

The geomagnetism detecting means 10 is connected to a DC amplifier 11. The A / D converter 12 is connected to a microcomputer 16 in addition to the DC amplifier 11. The microcomputer 16 is connected to the azimuth display switch 2, the correction switch 3, the display device 4, and the storage means 14 in addition to the A / D converter 12.

[Description of Circuit Operation: FIGS. 2 and 8] Next, the operation of the compass of the present invention for detecting geomagnetism, reading a correction value, and displaying the direction will be described with reference to FIGS. 2 and 8. I do.

The start of detection of terrestrial magnetism is determined by the azimuth display switch 2.
Start by pressing. Direction display switch 2
Is pressed (FIG. 8-81), the terrestrial magnetism detecting means 10 detects the terrestrial magnetism component (FIG. 8-82).

The fluxgate magnetic sensor can detect two plane components (X, Y) orthogonal to each other with respect to terrestrial magnetism. The output values of X and Y are output to the A / D converter 12 by the DC amplifier 11. The amplified voltage value is converted by the A / D converter 12 into a digital value that can be recognized by the microcomputer 16. The microcomputer 16 reads the correction value obtained from the input value (X, Y) from the elliptic equation calculation means 13 from the storage means 14 and corrects the above-mentioned value (X, Y) to the geomagnetic component (X
', Y') (FIG. 8-83).

The microcomputer 16 reads a correction value different from the correction value obtained by the elliptic equation calculation means 13 from the storage means 14 and outputs corrected values so that the amplitude values are the same as each other (FIG. 8). -84).

The azimuth calculating device 15 obtains the azimuth angle by the following equation: θ = arctan (Y ″ / X ″) (FIG. 8-85). The obtained azimuth angle is displayed on the display device 4 as information (for example, an arrow or a numerical value) that can be understood by the user (FIG. 8-8).
6).

[Explanation of Correction Operation Procedure: FIGS. 2, 3 and 6]
Next, a description will be given of an example of a procedure for calculating a correction value by the elliptic equation calculation means 13 and a circuit operation when the electronic compass of the present invention is magnetized.
This will be described with reference to FIG.

As shown in FIG. 3, the electronic compass is set to the correction mode by a switch operation or the like (see FIG. 6-6).
1) The correction switch 3 is directed in the direction A and remains in that direction.
Is pressed (FIG. 6-62). When the switch is depressed, the geomagnetism detecting means 10 operates to store the output value in that direction.
(FIG. 6-63).

Similarly, the correction switch 3 is also pressed in the direction B, which is a direction rotated 90 ° right from the direction A (FIG. 6).
-64), and stores the output value in the storage means 14 (FIG. 6-6).
5) The correction switch 3 is pressed in the direction C, which is a direction rotated 90 ° to the left (see FIG. 6-66), and the output value is stored in the storage means 14 (FIG. 6-67). When the output values in the three directions are stored, the elliptic equation calculation means 13 obtains an elliptic equation passing through the values of the three points by calculation (FIG. 6-6).
8).

[Explanation of correction value calculation: FIGS. 4 and 7]
The method for calculating the correction value of the electronic compass according to the second aspect of the present invention will be described in detail with reference to FIGS.

X output from the terrestrial magnetism detecting means 10 in the A direction
The component is given by: X1 = Kx · cos θ + m (1) where θ is the angle formed by the geomagnetism, m is the magnetization component, and X1 is the output value. Kx is a proportionality constant.

Next, the detected value X2 in the B direction is as follows: X2 = Kx · cos (θ−π / 2) (2)

Further, the detected value X3 in the C direction is: X3 = Kx · cos (θ + π / 2) (3)

Therefore, from the equations (1), (2) and (3), m = (X2 + X3) / 2 (4) Kx · Kx = (X1-m) · (X1-m) + (X3- m) · (X3-m) (5) can be obtained by a simple calculation (FIGS. 7-71 and 7-72).

Similarly, assuming that the Y component of magnetization is n, n = (Y2 + Y3) / 2 (6) Ky.Ky = (Y1-n). (Y1-n) + (Y3-n ) · (Y3-n) (7)

Therefore, equations (4), (5) and (6)
Since it is clear that the equation and the equation (7) show an equation of an ellipse, the center coordinates of the ellipse are (m, n), and the amplitude is Kx in the x direction and Ky in the y direction.

When the equation of the ellipse is obtained, the elliptic equation calculation means 13 completes the correction operation by storing the obtained correction value in the storage means 14 (FIG. 7-73).

As described above, according to the present invention, an accurate azimuth which eliminates a component magnetized by the compass itself and eliminates a calculation error due to a difference in detection sensitivity between the x component and the y component of the terrestrial magnetism detecting means 10 can be obtained. It can be displayed.

In the above embodiment, the magnetic sensing element is a flux gate type sensor. However, similar results can be obtained with a Hall element or a magnetoresistive element (MR element).

[0039]

As described in detail above, according to the present invention,
It is possible to provide an electronic azimuth meter capable of calculating a correct azimuth by easily and accurately correcting an error in a detection azimuth due to magnetization of the apparatus itself or deviation of an amplification factor of an amplifier.

[Brief description of the drawings]

FIG. 1 is a drawing showing a schematic configuration of an electronic compass according to an embodiment of the present invention.

FIG. 2 is a diagram showing a circuit configuration of an electronic compass according to the embodiment of the present invention.

FIG. 3 is a view showing a correction operation direction of the electronic compass according to the embodiment of the present invention.

FIG. 4 is a drawing showing an output ellipse obtained by the electronic compass of the present invention.

FIG. 5 is a drawing showing an output circle obtained by a conventional electronic compass.

FIG. 6 is a flowchart showing the azimuth correction processing of the electronic azimuth meter of the present invention.

FIG. 7 is a flowchart showing the azimuth correction processing of the electronic azimuth meter of the present invention.

FIG. 8 is a flowchart showing an azimuth angle calculation process of the electronic azimuth meter of the present invention.

[Explanation of symbols]

1: Case 2: Direction display switch
3: switch for correction 4: display device 10: geomagnetic detection means 1
1: DC amplifier 12: A / D converter 13: Elliptic equation calculation means 14: Storage means 15: Direction calculation device 16: Microcomputer

Claims (2)

[Claims] 1. A geomagnetism detecting means for detecting geomagnetism by two components orthogonal to each other, and a storage for storing an output value output from the geomagnetism detecting means when the geomagnetism is directed to any three directions orthogonal to each other on a horizontal plane. Means, an elliptic equation calculating means for obtaining an equation of an output elliptic trajectory when the compass is rotated once from the storage means, and a correction value obtained by the elliptic equation calculating means,
An electronic azimuth meter comprising: an azimuth calculation device for correcting an output value detected by the geomagnetic detection means to obtain an azimuth angle; and a display device for displaying the azimuth obtained by the azimuth calculation device. 2. A geomagnetism detecting means for detecting geomagnetism by two components orthogonal to each other, and an output value output from the geomagnetism detecting means when the geomagnetism is directed in any three directions orthogonal to each other on a horizontal plane. The elliptic equation is obtained from the output signal from the geomagnetic detection means when the magnetic field is directed in any of the three directions. The central coordinate of the ellipse and the maximum and minimum values of the two axes orthogonal to each other are obtained from the elliptic equation. And correcting the two output values detected by the geomagnetic detection means from the center coordinates and the maximum and minimum values of the ellipse.