KR100655936B1 - Azimuth calculation device and method thereof - Google Patents

Abstract

An azimuth calculation device and a method thereof are provided to prevent a calculation load of dip angle data from being aggravated by performing a dip angle data calculation selectively according to the degree of tilt angle. In an azimuth calculation device, a terrestrial magnetism measurement unit(110) detects X-axis and Y-axis terrestrial magnetism data, corresponding to an external terrestrial magnetism, by using X-axis and Y-axis terrestrial magnetism sensors. A tilt measurement unit(120) measures a tilt angle. A first calculation unit(130) computes dip angle data, corresponding to the present tilt angle, by using the previous and present tile angles and the X-axis and Y-axis terrestrial magnetism data in a case of the tile angle to be varied. A second calculation unit(140) computes virtual Z-axis terrestrial magnetism data by using the dip angle data, the present tile angle, and the X-axis and Y-axis terrestrial magnetism data. An azimuth calculation unit(150) computes an azimuth by using the virtual Z-axis terrestrial magnetism data and the X-axis and Y-axis terrestrial magnetism data.

Description

Azimuth calculation device and method

1 is a block diagram showing the configuration of an azimuth measuring device according to an embodiment of the present invention;

2 is a block diagram illustrating an example of a configuration of a geomagnetic measuring unit used in the azimuth measuring device of FIG. 1;

3 is a schematic diagram showing a spherical coordinate system;

4 is a schematic diagram for describing a process of calculating dip data according to a change in an inclination angle on a rectangular coordinate system of FIG. 3;

5 is a flowchart for explaining an azimuth measurement method according to an embodiment of the present invention, and

6 is a flowchart illustrating an example of a process of calculating dip data in the azimuth measurement method of FIG. 5.

Explanation of symbols on the main parts of the drawing

110: geomagnetic measuring unit 120: tilt measuring unit

130: first operation unit 140: second operation unit

150: azimuth calculation unit 111: drive signal generation unit

112: X-axis geomagnetic sensor 113: Y-axis geomagnetic sensor

114: signal processing unit 115: geomagnetic measuring control unit

116: memory

The present invention relates to an azimuth measuring device and a method thereof, and more particularly, to measuring azimuth using a two-axis geomagnetic sensor, azimuth compensation operation is performed by using dip data calculated by calculating dip data at a current position. The present invention relates to an azimuth measuring device and a method for calculating an accurate azimuth.

The geomagnetic sensor refers to a device that measures the strength and direction of the earth's magnetism that humans cannot feel. The geomagnetic sensor can generally be implemented as a flux-gate. An apparatus for calculating an azimuth using geomagnetic data calculated by a geomagnetic sensor is called an azimuth measuring device. The azimuth measuring device can be applied to various electronic products such as mobile phones, notebook computers, PDAs, and the like.

The azimuth measuring device may generally use a biaxial or triaxial geomagnetic sensor. In this case, if the geomagnetic sensor is tilted in the process of measuring the azimuth using the geomagnetic sensor, there is a possibility that the azimuth is incorrectly calculated. Accordingly, it is common to compensate the azimuth angle by using the inclination angle, that is, the pitch angle or the roll angle.

On the other hand, since the magnetic field is directional, the measured value varies depending on the user posture of the azimuth measuring device. That is, when the azimuth angle is measured while the azimuth measuring device is inclined at a predetermined angle, there is a problem that a value different from the actual azimuth angle can be measured. In order to solve this problem, azimuth compensation is performed to calculate the correct azimuth by measuring the inclination angle and compensating the influence of the inclination.

In this case, it is not necessary to consider the effect of dip angle (λ) in case of geomagnetic sensor using 3-axis fluxgate, but the effect of dip should be considered in case of geomagnetic sensor using 2-axis fluxgate. . This is because the two-axis fluxgate sensor includes only the X-axis and Y-axis fluxgates placed on the ground surface, so that the azimuth angle is measured using only the horizontal component values of the actual geomagnetic vector projected on the ground surface. Since the dip refers to the angle at which the geomagnetism is incident on the earth's surface, information about the dip is needed to consider the vertical component values of the actual geomagnetic vector.

Accordingly, in the conventional geomagnetic sensor using a two-axis fluxgate, a dip is arbitrarily set or a dip angle is input from an external device such as GPS to calculate an azimuth angle. However, even if located within the same area, the dip value may vary depending on the surrounding terrain. Accordingly, there is a problem that azimuth information may be distorted when the dip is arbitrarily set and used.

On the other hand, in the case of receiving a dip value from an external device such as GPS, there is a problem in that the size and manufacturing cost of the geomagnetic sensor increases because more equipment for communication with the external device is needed. In addition, since the 3-axis fluxgate geomagnetic sensor that does not require a dip needs an additional Z-axis fluxgate that must be installed in a direction perpendicular to the ground surface, the size increase is inevitable. Therefore, there is a problem that it is not suitable for use in small portable electronic devices.

The present invention is to solve the above-described problems, an object of the present invention is to calculate the azimuth data at the current position to perform the azimuth compensation operation, it is possible to azimuth compensation using accurate dip, thereby calculating the correct azimuth angle The present invention provides an azimuth measuring device and a method thereof.

Azimuth measuring device according to an embodiment of the present invention for achieving the above object, the geomagnetic measuring unit for detecting the X-axis and Y-axis geomagnetic data corresponding to the external geomagnetic using the X-axis and Y-axis geomagnetic sensor, A tilt measurement unit for measuring an inclination angle, a first calculation unit for calculating dip data corresponding to the current inclination angle by using a previous inclination angle and a current inclination angle and the X and Y axis geomagnetic data when the inclination angle is changed, the dip data, A second calculator configured to calculate virtual Z-axis geomagnetic data using the current tilt angle, the X-axis and Y-axis geomagnetic data, and the virtual Z-axis geomagnetic data, the X-axis and Y-axis geomagnetic data, and the inclination angle It includes an azimuth calculation unit for calculating the azimuth using.

Preferably, the first calculator is configured to calculate the dip data using a preset dip when the current tilt angle is less than a first threshold angle, and the X and Y axes when the current tilt angle is greater than or equal to a preset second threshold angle. One of the geomagnetic data may be calculated as the dip data, and if the current tilt angle is greater than or equal to the first threshold angle and less than the second threshold angle, a predetermined dip data operation may be performed to calculate the result value as the dip data.

Also preferably, the inclination angle may be at least one of a pitch angle and a roll angle.

More preferably, the first calculator may perform the dip data operation using different equations for each of the case where the roll angle is measured and the pitch angle is measured.

The second calculator may calculate the virtual Z-axis geomagnetic data by substituting a current inclination angle, dip data, X-axis and Y-axis geomagnetic data, and the like into a predetermined equation, and the azimuth calculator calculates the current inclination angle. The azimuth angle may be calculated by substituting virtual Z-axis geomagnetic data, X-axis, and Y-axis geomagnetic data into a predetermined equation.

More preferably, the geomagnetic measuring unit may output, as the X-axis and Y-axis geomagnetic data, a normalized value obtained by normalizing the output values of the X-axis and Y-axis geomagnetic sensors to a value within a preset range, respectively.

On the other hand, azimuth measurement method according to an embodiment of the present invention, (a) detecting the X-axis and Y-axis geomagnetic data corresponding to the external geomagnetism using the X-axis and Y-axis geomagnetic sensor, (b) the tilt angle Measuring, (c) calculating dip data corresponding to the current tilt angle by using a previous tilt angle and a current tilt angle and the X-axis and Y-axis geomagnetic data, and (d) the dip data, the current tilt angle, and X Calculating virtual Z-axis geomagnetic data using the axis and Y-axis geomagnetic data; and (e) calculating azimuth using the virtual Z-axis geomagnetic data, the X-axis and Y-axis geomagnetic data, and the current tilt angle. Steps.

Preferably, in the step (c), comparing the current tilt angle with a preset first and second threshold angles, and calculating the dip data using a preset dip when the current tilt angle is less than the first threshold angle. And when the current inclination angle is greater than or equal to a preset second critical angle, one of the X-axis and Y-axis geomagnetic data is calculated as the repetition data, and when the current inclination angle is greater than or equal to the first critical angle and less than the second critical angle, a predetermined dip. The data operation may be performed to calculate the result value as the dip data.

Also preferably, the inclination angle may be at least one of a pitch angle and a roll angle.

Meanwhile, in the step (c), when the roll angle is measured and the pitch angle is measured, the dip data may be calculated using a predetermined formula.

Also preferably, in step (d), the virtual Z-axis geomagnetic data may be calculated by substituting a current inclination angle, dip data, X-axis and Y-axis geomagnetic data, etc. into a predetermined equation, and (e) In step), the azimuth angle may be calculated by substituting the current tilt angle, virtual Z-axis geomagnetic data, X-axis and Y-axis geomagnetic data into a predetermined equation.

More preferably, the step (a) may output the normalized value obtained by normalizing the output values of the X-axis and Y-axis geomagnetic sensors to a value within a preset range, respectively, as the X-axis and Y-axis geomagnetic data.

Hereinafter, with reference to the accompanying drawings will be described in detail with respect to the present invention.

1 is a block diagram showing the configuration of an azimuth measuring device according to an embodiment of the present invention. According to FIG. 1, the azimuth measuring device includes a geomagnetic measuring unit 110, a tilt measuring unit 120, a first calculating unit 130, a second calculating unit 140, and an azimuth calculating unit 150.

The geomagnetic measuring unit 110 measures X-axis and Y-axis geomagnetic data corresponding to the geomagnetism by using mutually orthogonal X-axis and Y-axis geomagnetic sensors.

2 is a block diagram illustrating an example of a configuration of the geomagnetic measuring unit 110. According to FIG. 2, the geomagnetic measuring unit 110 includes a driving signal generator 111, an X-axis geomagnetic sensor 112, a Y-axis geomagnetic sensor 113, a signal processor 114, a geomagnetic measurement control unit 115, and a memory. 116.

The driving signal generator 111 generates a driving signal for driving the X-axis and Y-axis geomagnetic sensors 112 and 113. As the driving signal, a pulse wave or an inverted pulse wave may be used.

The X- and Y-axis geomagnetic sensors 112 and 113 may be implemented as fluxgates, respectively. Each fluxgate includes a magnetic core in the form of a square ring or bar, a drive coil wound around the magnetic core, and a detection coil. The driving coil serves to excite the magnetic core by receiving an electrical signal output from the driving signal generator 111, and the detection coil detects electromotive force induced from magnetism generated by driving the driving coil. Play a role.

On the other hand, the X-axis geomagnetic sensor 112 is disposed in the direction toward the front end of the azimuth measuring device (that is, the X-axis direction), the Y-axis geomagnetic sensor 113 is a direction perpendicular to the X-axis geomagnetic sensor It may be arranged in the direction toward the side (ie, Y-axis direction).

When a voltage component proportional to the intensity of an external magnetic field is derived from the detection coil, the signal processor 114 performs a series of processes such as amplifying and chopping the output coil, and then outputs a voltage value corresponding to each axis. do.

The geomagnetic measurement control unit 115 normalizes the voltage values output from the signal processor 114 to values within a preset range, and provides the normalized values to the first calculator 130 as X-axis and Y-axis geomagnetic data. Normalization can generally be in the range of -1 to 1.

Specifically, the geomagnetic measurement control unit 115 may perform normalization using the following equation.

In Equation 1, Xf and Yf are the actual output values of the X- and Y-axis geomagnetic sensors, respectively, Xf _norm and Yf _norm are normalization values of the X-axis and Y-axis, Xf _max and Xf _min are the maximum and minimum values of Xf, respectively. Yf _max and Yf _min are the maximum and minimum values of Yf, respectively, and α represents a fixed constant. In this case, α uses a value less than 1 so that the X- and Y-axis fluxgate output values can be mapped to values in the range of ± 1 in the horizontal state. Preferably, α can be set using a representative dip value of the region where the present azimuth measuring device is used. The dip in Korea is about 53 °, so we can put cos 53 ° ≒ 0.6 as α. On the other hand, Xf _max , Xf _min , Yf _max , and Yf _min measure the output value while rotating the azimuth measuring device at least one time in advance and set the maximum value and the minimum value among them. The set α, Xf _max , Xf _min , Yf _max , and Yf _min may be stored in the memory 116 and used during normalization.

Returning to the description of FIG. 1 again, the tilt measuring unit 120 measures the inclination, that is, the inclination angle of the azimuth measuring device. The inclination angle may be represented by a pitch angle and a roll angle. That is, the X-axis geomagnetic sensor is disposed in the direction toward the front end of the azimuth measurement device (ie, the X-axis direction), and the Y-axis geomagnetic sensor is directed toward the side of the azimuth measurement device in a direction perpendicular to the X-axis geomagnetic sensor (ie, , Y-axis direction), the roll angle is changed when the azimuth measuring device rotates about the X axis, and the pitch angle is changed when the azimuth measuring device rotates about the Y axis. The tilt measurement unit 120 may measure a pitch angle and a roll angle. The tilt measuring unit 120 may be specifically implemented as a two-axis or three-axis acceleration sensor. When implemented with a two-axis acceleration sensor, the pitch angle and the roll angle can be calculated using the following equation.

φ = sin ^-1 (a _y / g)

θ = sin ^-1 (a _x / g)

In Equation 2, g is gravity acceleration, φ is roll angle, θ is pitch angle, a _x is X-axis acceleration sensor output value, a _y represents the Y-axis acceleration sensor output value.

The first calculating unit 130 calculates the dip data using the X-axis and Y-axis geomagnetic data measured by the geomagnetic measuring unit 110 and the inclination angle measured by the tilt measuring unit 120. Dip data means the vertical component of the dip which vertically projected the dip in the Z-axis direction. Specifically, the dip data may be represented by sinλ. Where λ means dip.

3 is a schematic diagram illustrating a spherical coordinate system including a virtual Z axis. According to FIG. 3, the Z axis is disposed in a direction perpendicular to the plane formed by the X and Y axes. The X, Y, and Z axes geomagnetic data are the (X, Y, Z) coordinates of each point on the spherical coordinate system. Through this spherical coordinate system, when one or more of the pitch angle and the roll angle is not 0 °, that is, when the azimuth measuring device is driven while the inclination angle is generated, the calculated X-axis and Y-axis geomagnetic data are affected by the influence of geomagnetism. Are distorted by Accordingly, the virtual Z-axis geomagnetic data is calculated to convert the geomagnetic data on the spherical coordinate system to the horizontal coordinate system.

Virtual Z-axis geomagnetic data can be calculated using the following equation.

Here, Z _b means virtual Z-axis geomagnetic data, X, Y means X-axis and Y-axis geomagnetic data, and Z _h means dip data.

As described above, in the conventional azimuth measurement device, a value arbitrarily set for dip data or a value provided from an external device such as GPS is used. However, according to the present azimuth measuring device, the first calculating unit 130 directly calculates the dip data.

4 is a schematic diagram for explaining a process of obtaining a dip data calculation formula when only a roll angle of the inclination angle is changed. According to FIG. 4, assuming that a movement or posture transformation has occurred from any point a (Xa, Ya, Za) on the spherical coordinate system to point b (Xb, Yb, Zb), point a (Xa, Ya, Za) The reconstruction data at point b, that is, the repetition data of the current state is calculated using the inclination angle measured at point b (Xb, Yb, Zb) in.

According to FIG. 4, point a corresponds to a state where the roll angle is inclined by φ a, and point b corresponds to a state where the roll angle is inclined by φ b. The distance from the center of the spherical coordinate system to the center Ca of the cross section 410 to which point a belongs becomes the reconstruction data Z _ha of point a, and the distance to the center Cb of the cross section 420 to which point b belongs is point b Is the reproduction data of Z _hb . If the distance from the midpoint of the spherical coordinate system to the point a is Ra, and the distance to the point b is Rb, and Ra = Rb, it is possible to calculate the dip data at the point b using a trigonometric function.

Specifically, the first calculating unit 130 may calculate the dip data by using the following equation.

In Equation 4, Z _h represents dip data, φ _a represents a previous roll angle, and φ _b represents a current roll angle. In addition, x _a refers to the X-axis geomagnetic data, that is, the previous X-axis geomagnetic data at point a, and x _b refers to the Y-axis geomagnetic data, that is, the current X-axis geomagnetic data at point b.

Equation 4 is an equation that can be applied when only the roll angle is changed. Even when only the pitch angle is changed, the dip data may be calculated using the pitch angle difference between the previous point and the current point and the Y-axis geomagnetic data in the same manner as in FIG. 4. Specifically, when only the pitch angle is changed, the first calculator 130 may calculate the dip data by using the following equation.

In Equation 5, θ _a is the previous pitch angle, θ _b is the current pitch angle, y _a is the previous Y-axis geomagnetic data, and y _b is the current Y-axis geomagnetic data.

The second calculator 140 substitutes the reproduction data provided from the first calculator 130 into the above Equation 3 to calculate virtual Z-axis geomagnetic data at the current position. Specifically, when the current position is point b, the second calculator 140 calculates virtual Z-axis geomagnetic data at point b by using the following equation.

In Equation 6, Z _b means virtual Z-axis geomagnetic data at point b.

Meanwhile, the azimuth calculator 150 may include virtual Z-axis geomagnetic data provided from the second calculator 140, an X-axis and Y-axis geomagnetic data at a current position provided by the geomagnetic measuring unit 110, and a tilt measuring unit ( The azimuth angle is calculated using the current tilt angle provided at 120. The azimuth angle calculated by the azimuth calculator 150 is an azimuth angle in which the influence of the inclination angle is compensated. For example, when measured at point b, the azimuth calculator 150 may perform azimuth calculation using the following equation.

In Equation 7, ψ means azimuth angle.

Meanwhile, the first calculator 130 may calculate the dip data in various ways according to the size of the current tilt angle. Specifically, when the inclination angle is less than the first critical angle of the preset size, the dip data is calculated using the preset dip as it is. For example, if the dip is set to 53 degrees, sin (53) _0.8 is calculated as the dip data.

On the other hand, if the inclination angle is greater than or equal to the first critical angle and less than the second critical angle, the dip data is calculated by using Equation 4 or 5 described above. On the other hand, if the second critical angle or more, one of the X-axis and Y-axis geomagnetic data is calculated as the reproduction data. The first critical angle and the second critical angle may be set by the manufacturer or the user. For example, the first critical angle may be set to about 15 to 20 degrees, and the second critical angle may be set to about 80 to 85 degrees.

Referring to FIG. 4, when the roll angle of the inclination angle is less than the first critical angle, it corresponds to the band 1. In this case, since the degree of distortion due to the inclination angle is not large, it is preferable to calculate the dip data using the preset dip as it is.

On the other hand, the range below the first critical angle and below the second critical angle corresponds to band 2. In this case, since the distortion due to the inclination angle is large, it is preferable to accurately calculate the dip data using the above-described Equations 4 and 5, and to calculate the azimuth angle accordingly.

The range where the inclination angle is greater than or equal to the second critical angle corresponds to band 3. In this case, it can be seen that Z _h is almost similar to the X-axis geomagnetic data. Therefore, the X-axis geomagnetic data can be used as it is without performing a separate operation.

On the other hand, when only the pitch angle is changed, since Z _h is calculated to be almost the same value as the Y-axis geomagnetic data, the Y-axis geomagnetic data is calculated as dip data.

Meanwhile, in the azimuth measuring device of FIG. 1, the first calculating unit 130, the second calculating unit 140, and the azimuth calculating unit 150 may be implemented as one single microprocessor, or may be implemented as separate microprocessors. have.

5 is a flowchart illustrating a method for measuring azimuth according to an embodiment of the present invention. Referring to FIG. 5, first, the X-axis and the Y-axis geomagnetic data are calculated (S510). In this case, it is preferable to output normalized geomagnetic data by using a normalization formula such as Equation 1 described above.

Next, the inclination angle is calculated using the acceleration sensor (S520). The inclination angle may be one of a pitch angle and a roll angle. In FIG. 5, the inclination angle calculation is performed after the calculation of the X-axis and Y-axis geomagnetic data, but the order may be changed.

Next, dip data corresponding to the current tilt angle is calculated (S530). Dip data calculation may be performed using Equation 4 or 5 described above.

Accordingly, the virtual Z-axis geomagnetic data is calculated using the calculated dip data, the current tilt angle, the X-axis and the Y-axis geomagnetic data, and the like (S540). The virtual Z-axis geomagnetic data calculation may be performed using Equation 3 or 6 above.

Then, the azimuth angle is calculated using the calculated virtual Z-axis geomagnetic data (S550). The azimuth calculation may be performed using Equation 7 described above.

7 is a flowchart illustrating an example of calculating dip data in the azimuth measurement method of FIG. 6. According to FIG. 7, when the current tilt angle is detected, the first tilt angle is compared with the preset first and second threshold angles (S531). As a result of the comparison, if the current inclination angle is less than the first critical angle, the reproduction data is calculated using the preset dip as it is (S533).

On the other hand, if the current tilt angle is greater than or equal to the first critical angle and less than the second critical angle (S534), the replicating data is calculated using Equation 4 or 5 described above (S535).

On the other hand, if the current inclination angle is greater than or equal to the second critical angle, one of the X-axis and Y-axis geomagnetic data is calculated as the reproduction data (S536). Accordingly, it is possible to minimize the burden caused by the operation of the reproduction data.

As described above, according to the present invention, the dip data is calculated using the previous tilt angle and the current tilt angle, and the azimuth angle is compensated using the calculated dip data. As a result, an accurate azimuth angle can be calculated. In addition, since the repetition data operation is selectively performed according to the magnitude of the inclination angle, it is possible to prevent an increase in the repetition data operation burden.

In addition, although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the above-described specific embodiments, and the technology to which the present invention belongs without departing from the gist of the present invention as claimed in the claims. Various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

Claims (14)

Geomagnetic measuring unit for detecting the X-axis and Y-axis geomagnetic data corresponding to the external geomagnetism using the X-axis and Y-axis geomagnetic sensor; A tilt measuring unit measuring an inclination angle; A first calculator configured to calculate dip data corresponding to the current inclination angle by using a previous inclination angle and a current inclination angle and the X and Y axis geomagnetic data when the inclination angle is changed; A second calculator configured to calculate virtual Z-axis geomagnetic data using the dip data, the current tilt angle, and the X-axis and Y-axis geomagnetic data; And, And an azimuth calculation unit configured to calculate an azimuth using the virtual Z-axis geomagnetic data, the X-axis and Y-axis geomagnetic data, and the inclination angle. The method of claim 1, The first operation unit, When the current tilt angle is less than the first threshold angle, the dip data is calculated using a preset dip. If the current tilt angle is greater than or equal to a second predetermined threshold angle, one of the X-axis and Y-axis geomagnetic data is calculated as the repetition data, And assuming that the current tilt angle is greater than or equal to the first threshold angle and less than the second threshold angle, a predetermined dip data operation is performed to calculate a result value as the dip data. The method of claim 2, And the inclination angle is at least one of a pitch angle and a roll angle. The method of claim 3, The first operation unit, When the roll angle is measured among the inclination angles, the dip data operation is performed using Equation (1) below, and when the pitch angle is measured, the dip data operation is performed using Equation (2) below. Azimuth measuring device:

Where Z _h is the dip data, φ _a is the previous roll angle, φ _b is the current roll angle, θ _a is the previous pitch angle, θ _b is the current pitch angle, x _a is the previous X-axis geomagnetic data, and x _b is the current X-axis Geomagnetic data, y _a is the previous Y-axis geomagnetic data, and y _b is the current Y-axis geomagnetic data. The method of claim 4, wherein The second operation unit, Azimuth measuring device, characterized in that for calculating the virtual Z-axis geomagnetic data using the following equation:

Z _b is the virtual Z-axis geomagnetic data. The method of claim 5, The azimuth calculation unit, Azimuth measuring device, characterized in that for calculating the azimuth using the following formula:

Where ψ is azimuth. The method according to any one of claims 1 to 6, The geomagnetic measuring unit, And outputting a normalized value obtained by normalizing output values of the X-axis and Y-axis geomagnetic sensors to a value within a preset range, respectively, as the X-axis and Y-axis geomagnetic data. (a) detecting X-axis and Y-axis geomagnetic data corresponding to the external geomagnetism using the X-axis and Y-axis geomagnetic sensors; (b) measuring the tilt angle; (c) calculating dip data corresponding to the current tilt angle by using a previous tilt angle and a current tilt angle and the X-axis and Y-axis geomagnetic data; (d) calculating virtual Z-axis geomagnetic data using the dip data, the current tilt angle, the X-axis and Y-axis geomagnetic data; And, (e) calculating an azimuth angle using the virtual Z-axis geomagnetic data, the X-axis and Y-axis geomagnetic data, and the current inclination angle. The method of claim 8, Step (c) is, Comparing the current tilt angle with a preset first threshold angle and a second threshold angle; If the current inclination angle is less than the first critical angle, the reconstruction data is calculated using a preset dip. If the current inclination angle is greater than or equal to a second predetermined threshold angle, one of the X and Y-axis geomagnetic data is calculated as the reconstruction data. And if the current inclination angle is greater than or equal to the first threshold angle and less than the second threshold angle, a predetermined dip data operation is performed to calculate a result value as the dip data. The method of claim 9, And the inclination angle is at least one of a pitch angle and a roll angle. The method of claim 10, Step (c) is, When the roll angle is measured among the inclination angles, the dip data operation is performed using Equation (1) below, and when the pitch angle is measured, the dip data operation is performed using Equation (2) below. Azimuth measurement method:

Where Z _h is the compensation value, φ _a is the previous roll angle, φ _b is the current roll angle, θ _a is the previous pitch angle, θ _b is the current pitch angle, x _a is the previous X-axis geomagnetic data, and x _b is the current X-axis Geomagnetic data, y _a is the previous Y-axis geomagnetic data, and y _b is the current Y-axis geomagnetic data. The method of claim 11, In step (d), Azimuth measurement method, characterized in that for calculating the virtual Z-axis geomagnetic data using the following equation:

Z _b is the virtual Z-axis geomagnetic data. The method of claim 12, In step (e), Azimuth measurement method characterized in that for calculating the azimuth using the following equation:

Where ψ is azimuth. The method according to any one of claims 8 to 13, In step (a), And a normalizing value obtained by normalizing output values of the X-axis and Y-axis geomagnetic sensors to a value within a preset range, respectively, as the X-axis and Y-axis geomagnetic data.

Images