KR101298845B1 - Apparatus and method for calibrating azimuth magnetic sensor having object - Google Patents

Abstract

The present invention provides a method for correcting an azimuth angle of a geomagnetic sensor provided in an object. When the object is driven, a process of detecting a geomagnetic sensing signal by checking a change in a magnetic field and detecting the geomagnetic sensing signal by using the detected geomagnetic sensing signal Detecting a horizontal state with respect to the motion of the sensor; converting the detected horizontal state into a horizontal coordinate system; detecting a two-axis component of a planar magnetic vector defined in a plane parallel to the object; And extracting a correction coefficient by deriving a magnetic vector relationship expressed in an elliptic equation form from a vector component, and correcting the distortion of the geomagnetic sensing signal by using the extracted correction coefficient.

Description

Azimuth correction method and apparatus for geomagnetic sensor provided in an object {APPARATUS AND METHOD FOR CALIBRATING AZIMUTH MAGNETIC SENSOR HAVING OBJECT}

The present invention relates to an azimuth correction method and apparatus for a three-axis MEMS (Micro Electro Mechanical System) geomagnetic sensor capable of correcting an error in azimuth calculation.

Geomagnetic sensors are typically used to measure the orientation of observation points. The method of measuring the orientation by measuring the earth's magnetic field using a geomagnetic sensor, which is one of the fine magnetic fields, is based on displaying the orientation by measuring two-axis components of the earth's magnetic field at a position parallel to the earth's surface. The magnetic orientation is calculated from the biaxial components detected by the geomagnetic sensor.

However, the geomagnetic sensor that is currently used has a disadvantage that the sensor malfunctions when the sensor is inclined out of the horizontal position and the ground surface, causing an error in the orientation display. That is, when the conventional two-axis magnetic sensor is used, the application is limited to mobile robots such as mobile robots, unmanned vehicles such as unmanned aerial vehicles, and portable terminal devices such as mobile phones, laptops, etc. There is an urgent need for the development of geomagnetic sensors capable of displaying bearings.

The azimuth angle using the geomagnetic sensor is calculated using two plane geomagnetic vectors with the geomagnetic sensor lying on the plane, but in the case of MEMS geomagnetism sensors used directly attached to the fuselage, the plane is output to the three axis sensor output according to the rotation of the fuselage. Since the geomagnetic vectors are distributed, to obtain a planar geomagnetic vector regardless of the rotation of the fuselage, it is necessary to compensate the rotation angle with respect to the output of the 3-axis geomagnetic sensor.

The azimuth correction of the MEMS geomagnetic sensor needs to be corrected before use by using an additional sensor and reference device, and thus, an excessive calculation process and additional devices need to be provided.

Therefore, in the wireless unmanned vehicle such as an unmanned aerial vehicle and a mobile robot which requires accurate azimuth correction, the present invention corrects the distortion using only the output of the 3-axis geomagnetic sensor without any external device and performs the distortion correction when the 3-axis geomagnetic sensor is output. The present invention relates to a method and apparatus for correcting an azimuth angle of a geomagnetism sensor provided in an object for accurately calculating the azimuth angle in the 360 ° direction of the moving body.

According to one aspect of the invention, in the azimuth angle correction method of the geomagnetic sensor provided in the object, if the driving of the object is required, the process of detecting the geomagnetic sensing signal by checking the change in the magnetic field, and the detected geomagnetic sensing signal Detecting a horizontal state with respect to the movement of the object by using; converting the detected horizontal state into a horizontal coordinate system; detecting a two-axis component of a plane magnetic vector defined in a plane parallel to the object; Extracting a correction coefficient by deriving a magnetic vector relationship expressed in an elliptic equation form from the detected planar magnetic vector component, and correcting distortion of the geomagnetic sensing signal by using the extracted correction coefficient. It is characterized by.

According to another aspect of the present invention, in the azimuth correction device of the geomagnetic sensor provided in the object, a geomagnetic sensor unit for detecting a geomagnetic sensing signal by checking the change of the magnetic field, and the inclination for detecting the horizontal state of the movement of the object A sensor unit, a horizontal plane coordinate converting unit converting a horizontal state detected by the tilt sensor unit into a horizontal coordinate system, and controlling the driving of the object, and the geomagnetic sensing signal detected by the geomagnetic sensor unit through the horizontal plane coordinate changing unit Control to convert to a horizontal coordinate system to detect the two-axis component of the planar magnetic vector, extract the correction coefficient by deriving the magnetic vector relationship expressed in the form of an ellipse equation from the detected planar magnetic vector component, and corrects the geomagnetic distortion And a control unit for controlling to calculate the azimuth angle. .

The present invention uses an additional sensor and reference device by accurately calculating the azimuth angle for the 360 ° direction of the vehicle by applying a three-axis MEMS (Micro Electro Mechanical System) geomagnetic sensor in an unmanned vehicle requiring accurate azimuth correction. It is easy to calibrate during operation by using only the sensing signal of the 3-axis geomagnetic sensor, without the need for excessive calculation process, so it is possible to accurately measure the geomagnetic orientation of the vehicle.

1 is a flowchart illustrating a method of correcting an azimuth angle of a geomagnetic sensor provided in an object according to an exemplary embodiment of the present invention.
2 is a detailed block diagram of an azimuth correction device of a geomagnetic sensor provided in an object according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be appreciated that those skilled in the art will readily observe that certain changes in form and detail may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims. To those of ordinary skill in the art.

The present invention relates to a three-axis MEMS geomagnetic sensor, and more particularly, by applying the three-axis geomagnetic sensor in a wireless unmanned vehicle, such as an unmanned aerial vehicle and a mobile robot, by controlling the direction of movement of the azimuth angle When stabilizing the attitude of the vehicle, the distortion is corrected using only the output of the 3-axis geomagnetic sensor without any external device, and the distortion correction is repeatedly performed even when the 3-axis geomagnetic sensor is output. By precisely calculating the accuracy, additional sensors and reference devices do not require excessive computation and use only the sensing signal of the 3-axis geomagnetic sensor, so it is easy to calibrate during operation to provide a technology that can accurately measure the geomagnetic orientation of the vehicle.

In the following description, the objects described below will be understood to include, but are not limited to, terms representing moving objects such as an unmanned aerial vehicle and a mobile robot, for the convenience of description.

Hereinafter, an azimuth correction method of a geomagnetic sensor provided in an object according to an embodiment of the present invention will be described with reference to FIG. 1.

1 is a flowchart illustrating a method of correcting an azimuth angle of a geomagnetic sensor provided in an object according to an exemplary embodiment.

Referring to FIG. 1, when driving of an object is requested in step 110, in step 112, a change in a magnetic field is detected using a geomagnetic sensor provided in the object to detect a geomagnetic sensing signal.

In this case, the geomagnetic sensor refers to a three-axis MEMS geomagnetic sensor in an embodiment of the present invention, the three-axis MEMS geomagnetic sensor is integrally the two-axis geomagnetic sensor and the magnetic detection element as a hybrid IC It is made up. The biaxial geomagnetic sensor is formed using a substrate as a main body, and detects biaxial components of a magnetic vector defined by a plane parallel to the substrate. The magnetic detection element detects a component in a direction perpendicular to the plane of the magnetic vector. Accordingly, the three-axis geomagnetic sensor can detect three-axis components of the magnetic vector of the geomagnetic. As a magnetism detecting element, a magnetoresistive element such as a hall element that detects magnetism by the Hall effect, or a magnetoresistive element such as an MR element that detects magnetism due to a phenomenon in which the resistance changes according to the magnetization of the ferromagnetic material may be used. .

In operation 114, the horizontal state of the movement of the object is detected using the geomagnetic sensing signal detected in operation 112.

The three-axis geomagnetic sensor according to an embodiment of the present invention is formed on a substrate and the horizontal state detection operation of the object is performed through the three-axis magnetic sensor for detecting a three-dimensional magnetic vector and the inclination sensor for detecting the inclination angle of the substrate. .

In step 116, the detected horizontal state is converted into a horizontal coordinate system.

The conversion to the horizontal coordinate system is performed to compensate for the rotation angle with respect to the geomagnetic generated signal generated from the movement of the object.

In step 118, a biaxial component of a plane magnetic vector defined in a plane parallel to the object is detected.

An inclination sensor according to an embodiment of the present invention detects an inclination state, that is, a horizontal state, by detecting an inclination angle in the x-axis direction and an inclination angle in the y-axis direction defined as a plane parallel to the substrate.

In step 120, the planar magnetic vector component detected in step 118 is identified by an elliptic equation to derive a magnetic vector relationship expressed in the form of an elliptic equation.

In other words, the plane magnetic vector is converted from the geomagnetic sensing signal into a horizontal coordinate system and the center of the 2D graph is in the form of an ellipse at a predetermined position by a fixed or motion that distorts the plane magnetic vector. Assuming it is done.

In operation 122, the correction coefficients are extracted.

In this case, the correction coefficient refers to a coefficient for identifying an equation of an ellipse from a set of values continuously output according to the movement of the object from the geomagnetic sensor, wherein each coefficient extracted from the set of plane magnetic vectors is detected. The ratio of the center position, the long axis, and the short axis between the horizontal geomagnetism vector and the fixed or motion geomagnetism vector distorting the horizontal geomagnetism vector in the two-axis components of the planar magnetic vector.

In step 124, the distortion of the geomagnetic sensing signal is corrected using the correction coefficient extracted in step 122.

The geomagnetic distortion correction defines a relation by a fixed or motion that distorts a horizontal geomagnetic vector in two-axis components of the detected planar magnetic vector by using an arbitrary elliptic equation (Equation 1) and continuously obtains This is done by extracting each coefficient from a set of planar magnetic vectors.

In step 126, the azimuth calculation is performed using the geomagnetic sensing signal whose distortion is corrected in step 124. That is, a 360 ° azimuth is calculated by performing an inverse tangent calculation on the horizontal axis (x, y) geomagnetic vector in the two axis components of the detected planar magnetic vector.

The azimuth angle correction method of the geomagnetic sensor provided in the object according to an embodiment of the present invention has been described above.

Hereinafter, the azimuth correction device of the geomagnetic sensor provided in the object according to an embodiment of the present invention will be described in detail with reference to FIG. 2.

2 is a detailed block diagram of an azimuth correction device of a geomagnetic sensor provided in an object according to an embodiment of the present invention.

Referring to FIG. 2, the azimuth correction device 200 to which the present invention is applied includes a geomagnetic sensor unit 210, a tilt sensor unit 222, a horizontal coordinate transformation unit 224, an azimuth calculation unit 226, and a correction coefficient identification unit. 228 and the controller 230.

The geomagnetic sensor unit 210 detects a geomagnetic sensing signal by checking a change in the magnetic field.

Here, the geomagnetic sensor unit 210 is formed on a substrate and a horizontal state sensing operation of the object is performed through a three-axis magnetic sensor for detecting a three-dimensional magnetic vector and a tilt sensor for detecting an inclination angle of the substrate.

In the present invention, the geomagnetic sensor unit 210 refers to a 3-axis MEMS geomagnetic sensor, and the 3-axis MEMS geomagnetic sensor integrates a 2-axis geomagnetic sensor (not shown) and a magnetic detection element as a hybrid IC. It is composed of. The biaxial geomagnetic sensor is formed using a substrate as a main body, and detects biaxial components of a magnetic vector defined by a plane parallel to the substrate. The magnetic detection element detects a component in a direction perpendicular to the plane of the magnetic vector. Accordingly, the three-axis geomagnetic sensor can detect three-axis components of the magnetic vector of the geomagnetic. As a magnetism detecting element, a magnetoresistive element such as a hall element that detects magnetism by the Hall effect, or a magnetoresistive element such as an MR element that detects magnetism due to a phenomenon in which the resistance changes according to the magnetization of the ferromagnetic material may be used. .

The tilt sensor unit 222 detects a horizontal state of the movement of the object.

As described above, the geomagnetic sensor unit 210 is formed on a substrate and a horizontal state sensing operation of the object is performed through a three-axis magnetic sensor that detects a three-dimensional magnetic vector and a tilt sensor that detects an inclination angle of the substrate. do.

The horizontal plane transformation unit 224 converts the horizontal state detected by the tilt sensor unit 222 into a horizontal coordinate system.

The control unit 230 controls the driving of the object, and controls to convert the geomagnetic sensing signal detected from the geomagnetic sensor unit 210 into a horizontal coordinate system through the horizontal plane coordinate change unit 224 to obtain 2 plane magnetic vectors. Detects an axial component, derives a magnetic vector relationship expressed in the form of an ellipse equation from the detected planar magnetic vector component, and controls to extract the correction coefficient through the correction coefficient identification unit 228 to correct the geomagnetic distortion. Control to calculate the azimuth angle through the azimuth calculation unit 226.

At this time, the correction coefficient is a coefficient for identifying an elliptic equation from the set of values output from the geomagnetic sensor unit 210.

The control unit 230 converts the geomagnetic sensing signal from the geomagnetic sensing signal into a horizontal coordinate system and sets the center of the 2D graph in the form of an ellipse at a predetermined position by a fixed or motion that distorts the plane magnetic vector. Assume

In addition, the control unit 230 defines a fixed or motion relationship that distorts a horizontal geomagnetic vector and a horizontal axis geomagnetic vector in a biaxial component of the detected planar magnetic vector by an elliptic equation (Equation 2). And extract each coefficient from the planar magnetic vector set obtained continuously.

Here, each coefficient extracted from the planar magnetic vector set is a central position, a long axis, and a short axis between a horizontal axis geomagnetism vector and a fixed or motion geomagnetism vector distorting the horizontal axis geomagnetism vector in two-axis components of the detected plane magnetic vector. The ratio of is displayed.

The azimuth calculation unit 226 calculates a 360 ° azimuth by performing an inverse tangent calculation on the horizontal axis (x, y) geomagnetic vector from two axis components of the planar magnetic vector output from the horizontal plane coordinate conversion unit 224.

As described above, an operation related to an azimuth correction method and apparatus of a geomagnetic sensor provided in an object according to the present invention can be made. Meanwhile, in the above description of the present invention, specific embodiments have been described, but various modifications are included in the scope of the present invention. It can be carried out without departing. Accordingly, the scope of the present invention should not be limited by the illustrated embodiments, but should be determined by equivalents of the claims and the claims.

210: geomagnetic sensor unit 222: tilt sensor unit
224: horizontal plane coordinate conversion unit 226: azimuth calculation unit
228: correction coefficient identification unit 230: control unit

Claims (13)

In the azimuth angle correction method of the geomagnetic sensor provided in the object,
Detecting the geomagnetic sensing signal by checking a change of a magnetic field when driving of the object is required;
Detecting a horizontal state of the movement of the object by using the detected geomagnetic sensing signal;
Converting the detected horizontal state into a horizontal coordinate system and detecting a biaxial component of a planar magnetic vector defined in a plane parallel to the object;
Extracting a correction coefficient by deriving a magnetic vector relation expressed in an elliptic equation form from the detected planar magnetic vector components;
And correcting the distortion of the geomagnetic sensing signal using the extracted correction coefficients. The method of claim 1, wherein the correction coefficient is
Azimuth correction method of the geomagnetic sensor provided in the object, characterized in that the coefficient for identifying the equation of the ellipse from the set of values output from the geomagnetic sensor. The method of claim 1,
The center of the two-dimensional graph is transformed from the geomagnetic sensing signal to a horizontal coordinate system by a fixed magnetic plane and a fixed or motion distorting the planar magnetic vector.

Azimuth correction method of the geomagnetic sensor provided in the object, characterized in that it further comprises the step of assuming the form of an ellipse at a predetermined position. The object of claim 1, further comprising calculating a 360 ° azimuth angle by performing an inverse tangent calculation on a horizontal axis (x, y) geomagnetic vector in the two-axis components of the detected planar magnetic vector. Azimuth correction method of geomagnetic sensor provided. The method of claim 1, wherein the correcting of the geomagnetic distortion
A fixed or motion relationship that distorts a horizontal geomagnetic vector and a horizontal geomagnetic vector in two axis components of the detected planar magnetic vector is defined by an arbitrary elliptic equation, and each coefficient is obtained from the set of planar magnetic vectors successively obtained. Azimuth correction method of a geomagnetic sensor provided in an object characterized in that the extraction is performed. The method of claim 5, wherein each coefficient extracted from the plane magnetic vector set is
The ratio of the center position, the long axis, and the short axis between the horizontal axis geomagnetic vector and the fixed or motion geomagnetism vector distorting the horizontal axis geomagnetic vector in the two-axis components of the detected planar magnetic vector is displayed. Azimuth correction method of geomagnetic sensor. The method of claim 1, wherein the conversion to the horizontal coordinate system,
Compensating the azimuth angle of the geomagnetic sensor provided in the object characterized in that the compensation for the geomagnetic sensing signal generated from the movement of the object as much as the rotation angle. In the azimuth correction device of the geomagnetic sensor provided in the object,
A geomagnetic sensor unit for detecting a geomagnetic sensing signal by checking a change in the magnetic field;
An inclination sensor unit for detecting a horizontal state with respect to the movement of the object;
A horizontal plane coordinate converting unit converting the horizontal state detected by the tilt sensor unit into a horizontal coordinate system;
Controlling the driving of the object and converting the geomagnetic sensing signal detected from the geomagnetic sensor to a horizontal coordinate system through the horizontal plane coordinate changer to detect two-axis components of the planar magnetic vector, and detecting the detected planar magnetic vector component. Azimuth correction of the geomagnetic sensor provided in the object, characterized in that it comprises a control unit for deriving a magnetic vector relationship expressed in the form of an ellipse from the correction coefficient, correcting the geomagnetic distortion, and calculating an azimuth angle Device. The method of claim 8, wherein the correction coefficient,
And a coefficient for identifying an equation of an ellipse from a set of values output from the geomagnetic sensor unit. The method of claim 8, wherein the control unit,
An object characterized in that the plane magnetic vector is converted from the geomagnetic sensing signal into a horizontal coordinate system and the center of the 2D graph is assumed to be in the form of an ellipse at a predetermined position by a fixed or motion that distorts the plane magnetic vector. Azimuth correction device of geomagnetic sensor provided in the. 9. The method of claim 8,
And an azimuth calculation unit configured to calculate a 360 ° azimuth by performing inverse tangent calculation on a horizontal axis (x, y) geomagnetic vector from two axis components of the planar magnetic vector output from the horizontal plane coordinate conversion unit. Azimuth correction device of the geomagnetic sensor provided. The method of claim 8, wherein the control unit,
A fixed or motion relationship that distorts a horizontal geomagnetic vector and a horizontal geomagnetic vector in two axis components of the detected planar magnetic vector is defined by an arbitrary elliptic equation, and each coefficient is obtained from the set of planar magnetic vectors successively obtained. Azimuth correction device of the geomagnetic sensor provided in the object, characterized in that for controlling to extract. The method of claim 12, wherein each coefficient extracted from the plane magnetic vector set is
The ratio of the center position, the long axis, and the short axis between the horizontal axis geomagnetic vector and the fixed or motion geomagnetism vector distorting the horizontal axis geomagnetic vector in the two-axis components of the detected planar magnetic vector is displayed. Azimuth correction device of geomagnetic sensor.

Images