阅读说明：本技术 一种三维电子罗盘装置及实用校准方法 (Three-dimensional electronic compass device and practical calibration method ) 是由 张义 李东辉 于 2019-11-29 设计创作，主要内容包括：本发明涉及电子罗盘设备领域,尤其为一种三维电子罗盘装置及实用校准方法,包括顶盖、传感器面板、底壳以及连接器,所述顶盖、传感器面板和底壳自上而下由螺栓螺纹联结,所述传感器面板和连接器通过排针连接,所述底壳一侧设有分度盘平面,所述分度盘平面侧面设有多组分度盘侧板。本发明实用校准方法中的交叉耦合校准主要针对三轴磁力计的非正交安装误差以及线性度误差进行处理,水平校准可以消除硬磁干扰及部分软磁干扰,倾斜补偿校准主要融合三轴加速度计数据,从而实现电子罗盘的三维定向,可有效提高电子罗盘的方位角精度,而且主要的校准步骤集中在出厂校准,客户校准部分简单实用有效,更加拓宽了三维电子罗盘的应用领域。(The invention relates to the field of electronic compass equipment, in particular to a three-dimensional electronic compass device and a practical calibration method. The cross coupling calibration in the practical calibration method mainly aims at the non-orthogonal installation error and the linearity error of the three-axis magnetometer to be processed, the horizontal calibration can eliminate hard magnetic interference and partial soft magnetic interference, the tilt compensation calibration mainly integrates the data of the three-axis accelerometer, thereby realizing the three-dimensional orientation of the electronic compass, effectively improving the azimuth angle precision of the electronic compass, concentrating the main calibration steps on factory calibration, leading the client calibration part to be simple, practical and effective, and widening the application field of the three-dimensional electronic compass.)

1. A three-dimensional electronic compass device and a practical calibration method thereof are disclosed, wherein the device comprises a top cover (1), a sensor panel (2), a bottom shell (3) and a connector (4), and is characterized in that: the sensor comprises a top cover (1), a sensor panel (2) and a bottom shell (3), wherein the top cover, the sensor panel (2) and the bottom shell (3) are connected from top to bottom through bolts and threads, the sensor panel (2) is connected with a connector (4) through a pin header, an index plate plane (5) is arranged on one side of the bottom shell (3), and a multi-component index plate side plate (6) is annularly arranged on the index plate plane (5).

2. The three-dimensional electronic compass device and the practical calibration method thereof according to claim 1, wherein: and a three-axis accelerometer and a three-axis magnetometer are arranged on the sensor panel (2).

3. The three-dimensional electronic compass device and the practical calibration method thereof according to claim 1, wherein: the practical calibration method comprises the following steps: the calibration, horizontal calibration and tilt compensation calibration are coupled in crossed axes, and the coordinate system adopts a northeast (X-Y-Z) Cartesian system.

4. The three-dimensional electronic compass device and the practical calibration method thereof according to claim 3, wherein: the cross-coupling calibration is mainly used for processing non-orthogonal installation errors and linearity errors of the three-axis magnetometer, the calibration is carried out in an environment relatively far away from magnetic interference, the calibration belongs to front-end data calibration, horizontal calibration eliminates hard magnetic interference and partial soft magnetic interference, inclination compensation calibration mainly fuses three-axis accelerometer data, and vectors output by the magnetometer are projected on a horizontal plane, so that three-dimensional orientation of the electronic compass is achieved.

5. The three-dimensional electronic compass device and the practical calibration method thereof according to claim 1, wherein: the practical calibration method comprises the following steps:

the first step is as follows: acquiring and recording magnetometer original data, performing cross coupling calibration, and calculating parameters according to a three-axis magnetometer cross coupling model:

where Mi (i ═ x, y, z) is the calibrated magnetometer vector, Ki (i ═ x, y, z) represents scale factors, eij (i, j ═ x, y, z) represents the non-orthogonal error term between three pairwise orthogonal axes, Mbi (i ═ x, y, z) represents the raw value of the magnetometer, bi0(i ═ x, y, z) represents the zero bias value of the magnetometer; acquiring the vector of the original magnetometer after the moving average by using a twelve-position method, and obtaining each coefficient by using a cross-coupling model through a least square method;

the second step is that: mraw ═ M obtained after the first cross-coupling calibration_xM_yM_z]^TPerforming the second horizontal calibration, slowly rotating the Mraw sample on the platform for more than one circle, and recording and storing data; due to projection of earth magnetic field vector on horizontal planeThe shadow is a fixed vector and points to the magnetic north direction, and M in the process of rotating one circle can be acquired according to the characteristic_xAnd M_yA value; then, the magnetic vectors in the X and Y directions are predicted to be a standard circle in the process of one rotation: mn²＝M_x ²+M_y ²However, in practice, due to the magnetic field interference of the surrounding environment, the actual model of the magnetic field interference is changed into an eccentric ellipse, and a normalized circle is obtained through least square fitting of nonlinear constraint as shown in fig. 3, which is also called two-dimensional calibration at this time, and can satisfy the calibration method used in the horizontal environment;

the third step: performing a third step of tilt compensation calibration on the basis of the two-dimensional calibration in the second step, wherein for most working conditions, the electronic compass can work in a non-horizontal environment, and the quantity Mz of the Z-axis magnetometer needs to be introduced;

the fourth step: projecting the vector of the three-axis magnetometer on a horizontal plane, and calculating the horizontal attitude angles roll and pitch of the electronic compass by using the accelerometer, wherein the directions of the coordinate systems of the accelerometer and the magnetometer are consistent with the direction of the electronic compass (b is a front right lower system):

roll＝atan2(-Ay，-Az)

pitch＝asin(Ax)；

the fifth step: rotating the Z axis of the electronic compass along the horizontal direction, collecting and recording Mz, and predicting that the calibrated three-dimensional magnetic vector graph is an ellipsoid:

And a sixth step: projecting the vector Hm onto a horizontal plane, obtaining horizontal components Xvalue and Yvalue:

the seventh step: calculating the azimuth angle from the XValue and Yvalue obtained in the third step: yaw is atan2(Yvalue, Xvalue) and north is positive.

6. The three-dimensional electronic compass device and the practical calibration method thereof according to claim 1, wherein: eight groups of the dividing plate side plates (6) are arranged, and the dividing plate plane (5) is equally divided into eight areas by the dividing plate side plates (6).

Technical Field

The invention relates to the field of electronic compass equipment, in particular to a three-dimensional electronic compass device and a practical calibration method.

Background

Scientific and technological progress supports socio-economic development fate gradually, and navigation orientation technology has also slowly merged into people daily life, and under the big environment that present science and technology soared, navigation orientation technology has been accurately struck in aerospace, naval vessel navigation, intelligent weapon, and individual soldier's system even uses, and more in recent years, be applied to unmanned aerial vehicle, AGV dolly, unmanned vehicle, intelligent robot and autopilot field, has emerged multiple navigation mode according to the environment difference of using: GPS satellite navigation, the Beidou system of China, inertial navigation, map matching navigation, radar navigation, visual navigation, and multi-information fusion combined navigation are endlessly developed, however, with the development of the MEMS technology, the navigation device is gradually noticed by people in terms of volume, size, and speed, not only the navigation orientation accuracy is required, and the response speed of the equipment needs to be improved, such as GPS navigation can lose star and lock in a tunnel or a building sheltered environment, the north seeker has a long north seeking time, the electronic compass needs to work in a static environment, inertial navigation cannot be used for long-time navigation, the self-alignment time is long generally, the advantages and disadvantages exist in short, the application requirements are difficult to meet uniformly, the electronic compass adopts an MEMS integration technology, utilizes a natural earth magnetic field, does not need long-time orientation, the characteristics of low cost, low power consumption, high performance and high precision are favored by a plurality of engineering fields.

The electronic compass integrates a three-axis accelerometer and a three-axis magnetometer, measures specific force acceleration and magnetic field vector respectively, is an ideal orientation combination in theory, however, as the earth magnetic field is a weak magnetic field, magnetic interference of different degrees exists in practical application occasions, which causes inaccurate magnetic azimuth, therefore, the calibration of the electronic compass is a key premise for practical application, the traditional calibration method is to directly measure the multi-position angle between 0 and 360 degrees, record the angle error of each position by using a non-magnetic turntable, perform linear interpolation method compensation, namely, the compensation of the error of the compass, can be effectively applied, but when the environment changes, the error correction needs to be carried out again, the process is complicated, most occasions do not meet the calibration condition, therefore, a practical calibration method of the three-dimensional electronic compass is particularly important for the application of the electronic compass.

Disclosure of Invention

The present invention is directed to a three-dimensional electronic compass device and a practical calibration method thereof, so as to solve the problems mentioned in the background art.

In order to achieve the purpose, the invention provides the following technical scheme:

a three-dimensional electronic compass device comprises a top cover, a sensor panel, a bottom shell and a connector, wherein the top cover, the sensor panel and the bottom shell are connected through bolts and threads from top to bottom, the sensor panel is connected with the connector through pins, an index plate plane is arranged on one side of the bottom shell, and a multi-component index plate side plate is annularly arranged on the index plate plane.

Preferably, the sensor panel is provided with a three-axis accelerometer and a three-axis magnetometer, and the coordinate system adopts a northeast X-Y-Z Cartesian system.

Preferably, the practical calibration method comprises: cross-axis coupling calibration, horizontal calibration, and tilt compensation calibration.

Preferably, the cross-coupling calibration is mainly performed for non-orthogonal installation errors and linearity errors of the three-axis magnetometer, the calibration is performed in an environment relatively far away from magnetic interference, and belongs to front-end data calibration.

Preferably, the practical calibration method comprises the following steps:

the first step is as follows: acquiring and recording magnetometer original data, performing cross coupling calibration, and calculating parameters according to a three-axis magnetometer cross coupling model:

where Mi (i ═ x, y, z) is the calibrated magnetometer vector, Ki (i ═ x, y, z) represents scale factors, eij (i, j ═ x, y, z) represents the non-orthogonal error term between three pairwise orthogonal axes, Mbi (i ═ x, y, z) represents the raw value of the magnetometer, bi0(i ═ x, y, z) represents the zero bias value of the magnetometer; acquiring the vector of the original magnetometer after the moving average by using a twelve-position method, and obtaining each coefficient by using a cross-coupling model through a least square method;

the second step is that: mraw ═ M obtained after the first cross-coupling calibration_xM_yM_z]^TPerforming the second horizontal calibration, slowly rotating the Mraw sample on the platform for more than one circle, and recording and storing data; because the projection of the earth magnetic field vector on the horizontal plane is a fixed vector and points to the magnetic north direction,m in the process of one rotation can be acquired according to the characteristic_xAnd M_yA value; then, the magnetic vectors in the X and Y directions are predicted to be a standard circle in the process of one rotation: mn²＝M_x ²+M_y ²However, in practice, due to the magnetic field interference of the surrounding environment, the actual model of the magnetic field interference is changed into an eccentric ellipse, and a normalized circle is obtained through least square fitting of nonlinear constraint as shown in fig. 3, which is also called two-dimensional calibration at this time, and can satisfy the calibration method used in the horizontal environment;

the third step: performing a third step of tilt compensation calibration on the basis of the two-dimensional calibration in the second step, wherein for most working conditions, the electronic compass can work in a non-horizontal environment, and the quantity Mz of the Z-axis magnetometer needs to be introduced;

the fourth step: and projecting the vector of the three-axis magnetometer on a horizontal plane, and calculating the horizontal attitude angles roll and pitch of the electronic compass by using the accelerometer, wherein the directions of the coordinate systems of the accelerometer and the magnetometer are consistent with the direction of the electronic compass (b is a front right lower system).

roll＝atan2(-Ay，-Az)

pitch＝asin(Ax)；

The fifth step: rotating the Z axis of the electronic compass along the horizontal direction, collecting and recording Mz, and predicting that the calibrated three-dimensional magnetic vector graph is an ellipsoid:

except for M_iAnd R, exactly nine unknowns, by morphing a-i to correspond to the model of claim 1, and combining the horizontal data in the second step, one can solve the new magnetic vector Hm ═ Hmx, Hmy, Hmz]^T；

And a sixth step: projecting the vector Hm onto a horizontal plane, obtaining horizontal components Xvalue and Yvalue:

the seventh step: calculating the azimuth angle from the XValue and Yvalue obtained in the third step: yaw is atan2(Yvalue, Xvalue) and north is positive.

Preferably, the indexing disc side plates are provided with eight groups, and the indexing disc side plates equally divide the indexing disc plane into eight areas.

Compared with the prior art, the invention has the beneficial effects that:

1. the practical calibration method comprises the following steps: cross-axis coupling calibration, horizontal calibration and tilt compensation calibration; the cross coupling calibration is mainly used for processing non-orthogonal installation errors and linearity errors of the three-axis magnetometer, the calibration is carried out in an environment relatively far away from magnetic interference, and the calibration belongs to front-end data calibration; the horizontal calibration can eliminate hard magnetic interference and part of soft magnetic interference; the inclination compensation calibration mainly integrates the data of the three-axis accelerometer, and projects the vector output by the magnetometer on a horizontal plane, so that the three-dimensional orientation of the electronic compass is realized.

Drawings

FIG. 1 is a block diagram of a three-dimensional electronic compass device and a practical calibration method according to the present invention;

FIG. 2 is a diagram of a structure of an index plate of the three-dimensional electronic compass device and a practical calibration method according to the present invention;

FIG. 3 is a two-dimensional calibration chart of the three-dimensional electronic compass device and the practical calibration method according to the present invention;

fig. 4 is a flowchart of a practical calibration method of the three-dimensional electronic compass device and the practical calibration method according to the present invention.

In the figure: 1-top cover, 2-sensor panel, 3-bottom shell, 4-connector, 5-graduated disk plane, 6-graduated disk side plate.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and all other embodiments obtained by a person of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the protection scope of the present invention.

Referring to fig. 1-4, the present invention provides a technical solution:

a three-dimensional electronic compass device and a practical calibration method thereof are disclosed, the device comprises a top cover 1, a sensor panel 2, a bottom shell 3 and a connector 4, the top cover 1, the sensor panel 2 and the bottom shell 3 are connected by bolts and threads from top to bottom, the sensor panel 2 and the connector 4 are connected through pins, a three-axis accelerometer and a three-axis magnetometer are arranged on the sensor panel 2, a coordinate system adopts a northeast X-Y-Z Cartesian system, an index plate plane 5 is arranged on one side of the bottom shell 3, a multi-component dial side plate 6 is annularly arranged on the index plate plane 5, the index plate side plate 6 is provided with eight groups, and the index plate plane 5 is equally divided into eight regions by the index plate side plate 6, the practical calibration method: the method mainly comprises the following steps of cross-axis coupling calibration, horizontal calibration and tilt compensation calibration, wherein the cross-axis coupling calibration is mainly used for processing non-orthogonal installation errors and linearity errors of a three-axis magnetometer, the calibration is carried out in an environment relatively far away from magnetic interference, the method belongs to front-end data calibration, the horizontal calibration eliminates hard magnetic interference and part soft magnetic interference, the tilt compensation calibration mainly fuses three-axis accelerometer data, and vectors output by the magnetometer are projected on a horizontal plane, so that three-dimensional orientation of the electronic compass is realized, and the method comprises the following practical calibration method steps:

the first step is as follows: acquiring and recording magnetometer original data, performing cross coupling calibration, and calculating parameters according to a three-axis magnetometer cross coupling model:

where Mi (i ═ x, y, z) is the calibrated magnetometer vector, Ki (i ═ x, y, z) represents scale factors, eij (i, j ═ x, y, z) represents the non-orthogonal error term between three pairwise orthogonal axes, Mbi (i ═ x, y, z) represents the raw value of the magnetometer, bi0(i ═ x, y, z) represents the zero bias value of the magnetometer; acquiring the vector of the original magnetometer after the moving average by using a twelve-position method, and obtaining each coefficient by using a cross-coupling model through a least square method;

the second step is that: mraw ═ M obtained after the first cross-coupling calibration_xM_yM_z]^TPerforming the second horizontal calibration, slowly rotating the Mraw sample on the platform for more than one circle, and recording and storing data; because the projection of the earth magnetic field vector on the horizontal plane is a fixed vector and points to the magnetic north direction, the M in the process of rotating one circle can be acquired according to the characteristic_xAnd M_yA value; then, the magnetic vectors in the X and Y directions are predicted to be a standard circle in the process of one rotation: mn²＝M_x ²+M_y ²However, in practice, due to the magnetic field interference of the surrounding environment, the actual model of the magnetic field interference is changed into an eccentric ellipse, and a normalized circle is obtained through least square fitting of nonlinear constraint as shown in fig. 3, which is also called two-dimensional calibration at this time, and can satisfy the calibration method used in the horizontal environment;

the third step: performing a third step of tilt compensation calibration on the basis of the two-dimensional calibration in the second step, wherein for most working conditions, the electronic compass can work in a non-horizontal environment, and the quantity Mz of the Z-axis magnetometer needs to be introduced;

the fourth step: and projecting the vector of the three-axis magnetometer on a horizontal plane, and calculating the horizontal attitude angles roll and pitch of the electronic compass by using the accelerometer, wherein the directions of the coordinate systems of the accelerometer and the magnetometer are consistent with the direction of the electronic compass (b is a front right lower system).

roll＝atan2(-Ay，-Az)

pitch＝asin(Ax)；

The fifth step: rotating the Z axis of the electronic compass along the horizontal direction, collecting and recording Mz, and predicting that the calibrated three-dimensional magnetic vector graph is an ellipsoid:

except for M_iAnd R, exactly nine unknowns, which can be solved by morphing a-i to correspond to the model of claim 1, in combination with the horizontal data in the second stepTo obtain new magnetic vector Hm ═ Hmx, Hmy, Hmz]^T；

And a sixth step: projecting the vector Hm onto a horizontal plane, obtaining horizontal components Xvalue and Yvalue:

the seventh step: calculating the azimuth angle from the XValue and Yvalue obtained in the third step: yaw is atan2(Yvalue, Xvalue) and north is positive.

As shown in fig. 2, the electronic compass can be placed on one side of the plane 5 of the graduated disk, the side of the bottom case 3 of the electronic compass is close to the side plate 6 of the graduated disk, the magnetic azimuth output by the electronic compass is recorded according to the eight side plates of the graduated disk, the position is changed every 45 degrees, the relative error amount is calculated, and the calibration quality of the electronic compass is measured by the standard deviation of the error amount.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.