CN104198973A - Calibration device of vector magnetometer - Google Patents

Abstract

The invention relates to a vector magnetometer calibration device, which mainly includes a vector magnetometer, a base, an outer ring rotation device, a middle ring rotation device and an inner ring rotation device, the inner ring rotation device is fixed with a vector magnetometer; the vector magnetometer is fixed on the inner ring Rotate the surface and rotate the inner ring rotation axis to make the magnetometer perform single-axis 360° transformation. Turning the rotating shaft of the middle ring enables the magnetometer and the inner ring to perform 360° transformation together, and the rotating shaft of the inner ring can also freely rotate 360°. Turning the rotation axis of the outer ring makes the magnetometer, the rotation surface of the middle ring and the rotation surface of the inner ring perform 360° attitude transformation together. The beneficial effects of the present invention are: when the outer ring rotation shaft is rotated, the inner ring rotation shaft and the middle ring rotation shaft can also freely rotate 360°, so that the magnetometer sensor has three degrees of freedom attitude transformation space. In the process of attitude transformation, the acquisition device records the magnetic field change value of the magnetometer in real time to provide more realistic original error information for error calibration.

Description

A vector magnetometer calibration device

technical field

The invention relates to a calibration device, more precisely, a vector magnetometer calibration device.

Background technique

The three-axis fluxgate magnetometer can measure the vector (three-component) information of the space geomagnetic field, and can obtain the size and direction data of the coordinate position under certain conditions. Therefore, compared with the total field scalar magnetometer, it can A more comprehensive description of the ambient magnetic field. The full tensor system based on the three-axis magnetometer and the vector gradiometer are widely used in aeromagnetic survey, marine magnetic survey and magnetic target detection.

In theory, the three single-component magnetic probes of the three-axis fluxgate magnetometer should be perpendicular to each other and satisfy the orthogonal coordinate system criterion. However, due to the difference in the level of technology and the degree of hardware calibration, there will be a certain angle error in the installation angles of the three magnetic probes, which will bring errors to the combined total field. Moreover, the sensitivity problem of the three-channel acquisition circuit and the zero point offset problem of the magnetic probe will bring errors to the magnetic field measurement.

In order to better meet the requirements of high-precision magnetic measurement, the above-mentioned errors need to be corrected. Assume that the corresponding relationship between the ideal coordinate system and the actual coordinate system of the probe is shown in Figure 1 below: the coordinate system OXYZ is the ideal coordinate system, and the coordinate system OX ₁ Y ₁ Z ₁ is the actual coordinate system, where the plane OXY and the plane OX ₁ Y are coplanar, and the axis OZ coincides with the axis OZ ₁ , and the axis OY ₁ is any axis in the vector space, depending on the actual situation; ∠a is the angle between the axis OX and the axis _OX1 , ∠b is the angle between the axis OY ₁ and the plane OXY ∠c is the angle between the projection OY2 of the axis OY1 on the plane OXY and the axis OY.

In order to correct errors such as the non-orthogonality of the vector magnetometer, software methods are commonly used at home and abroad for correction processing, that is, the vector magnetometer is fixed in the environmental magnetic field, and then the magnetic field data in different attitudes are obtained by rotating the magnetometer sensor. , and then perform error correction on the obtained magnetic field data through various calibration algorithms to obtain the calibrated magnetic field vector information. However, in the available literature, the acquisition of vector magnetometer data often has limitations, some only have dozens of sets of data, some only perform regional calibration on the horizontal plane (or vertical plane), and some When testing data, only swinging the magnetometer sensor aimlessly in the vector space cannot reflect the error information of the magnetometer in a targeted and comprehensive manner.

In the document "Error Correction of Fluxgate Sensor under Arbitrary Attitude Change", it is proposed to use the least squares method to accurately estimate the correction parameters of the fluxgate sensor and correct the steering error at this point. The document mentions that the steering error at the correction point can be reduced after calibration. as small as 25.8%. However, the original magnetometer data used for calibration in this document is only 75. These data cannot fully reflect the attitude information of the vector magnetometer, so the calibrated coefficients have limitations. When the vector magnetometer is transformed to a new attitude, This coefficient cannot correctly reflect the error information.

In the literature "Research on Error Correction of Three-axis Magnetometer Based on FLANN", a three-axis magnetometer error correction method based on Function Linked Neural Network (FLANN) is proposed. The literature first conducts detailed analysis and theoretical calculations on the measurement of the parameters of the three-axis magnetometer system, and then designs a mathematical model in the form of a matrix to correct the error. It is mentioned in the literature that according to the data measured by the actual geomagnetic field, the steering error of the three-axis magnetometer is corrected from 800nT to below 12nT. However, there are only 20 sets of actual measured data in the literature, and only 20 sets of data cannot fully reflect the non-orthogonal error information of the three-axis magnetometer, so it also has limitations.

In the literature "Analysis and Correction of Orthogonal Error of Three-axis Magnetometer", the problem of non-orthogonality and inconsistent sensitivity caused by measurement error is analyzed and theoretically calculated in detail, and on this basis, the three-axis magnetometer is proposed. Orthogonal transformation, the experimental results show that the method in the literature can correct the orthogonality error of the three-axis magnetometer to less than 0.05°. However, there are only 40 sets of data used for calibration in the literature, which also cannot fully reflect the true error of the three-axis magnetometer, so it also has limitations.

Contents of the invention

The purpose of the present invention is to overcome the problems existing in the above-mentioned prior art, and to provide a vector magnetometer calibration device, which adopts an omnidirectional three-degree-of-freedom non-magnetic rotating device, and the vector magnetometer can realize omnidirectional acquisition during the calibration process. The magnetic data under any attitude in the vector space provides complete, efficient and accurate hardware support for the out-of-orthogonality calibration of the vector magnetometer.

The purpose of the present invention is accomplished through the following technical solutions. This vector magnetometer calibration device mainly includes a vector magnetometer, a base, an outer ring rotation device, a middle ring rotation device and an inner ring rotation device, wherein a vector magnetometer is fixed in the center of the inner ring rotation device, and by rotating the outer ring rotation device , the middle ring rotating device and the inner ring rotating device to change the attitude of the vector magnetometer, and collect and record the data of the vector magnetometer during the rotation process; the vector magnetometer is connected to the industrial computer through a signal transmission line; the outer ring is marked on the base Rotary shaft dial, the outer ring rotating device includes a rotating pillar, an outer ring locking knob, a rotating surface, an outer ring rotating shaft and a fixed disc, wherein the rotating pillar is perpendicular to the rotating surface, and the two are fixed by non-magnetic titanium alloy screws. There is one on the left and right of the pillar, the rotating surface is set in the chute of the base through the rotating shaft of the outer ring, and the rotating shaft of the outer ring is clamped with the chute of the base through the fixed disc; Tighten the knob, the rotating bearing, the rotating rod and the movable handle. The rotating ring of the middle ring is installed in the round hole at the top of the rotating pillar through the rotating bearing. base, and can rotate freely on the horizontal plane with the outer ring; the rotating rod is fixed on one end of the rotating bearing of the middle ring, the movable handle is fixed on the other end of the rotating bearing of the middle ring, and the dial is rigidly fixed on one end of the rotating ring of the middle ring for indicating The scale value of the rotation; the inner ring rotating device includes the inner ring rotating ring, the magnetometer mounting surface, the scale indicator plate, the knob and the locking rod, the inner ring rotating ring is installed on the inner side of the middle ring rotating ring by the inner ring rotating bearing, and the inner ring rotates The bearing rotates 360° for the rotating shaft of the inner ring and is perpendicular to the rotating bearing of the middle ring. The magnetometer mounting surface is fixed on the inner ring rotating ring by titanium alloy screws, and the center of the magnetometer mounting surface is provided for installing the vector magnetometer. The screw holes are installed, and the scale indicator plate is used to indicate the angle of rotation of the inner ring rotating ring; the inner ring rotating ring is rotated by rotating the knob, and then the vector magnetometer on the magnetometer mounting surface is driven to change the attitude; the rotation axis of the outer ring rotates with the middle ring The axes are perpendicular to each other, the rotation axis of the middle ring and the rotation axis of the inner ring are perpendicular to each other, and the vector magnetometer is located at a point where the rotation axis of the outer ring, the rotation axis of the middle ring and the rotation axis of the inner ring intersect.

The base is provided with base through holes for fixing.

The rotating support is provided with a signal line traction rod for guiding the signal transmission line to the outside of the calibration device, and the signal line traction bar is provided with a signal line traction clamp for clamping the signal transmission line.

The locking rod is installed in the inner hole of the knob, by rotating the locking rod, and then through the thread rotation of the outer wall of the locking rod, the locking rod is promoted to move forward or backward, thereby locking or releasing the rotation of the inner ring ring.

The beneficial effects of the present invention are as follows: the vector magnetometer is fixed in the center of the rotation surface of the inner ring by a non-magnetic titanium alloy screw, and the rotation axis of the inner ring is rotated so that the magnetometer performs a single-axis 360° attitude transformation at this point in the vector space, and the magnetometer During the rotation, the device records the magnetic field change value of the magnetometer in real time. Turning the rotating shaft of the middle ring makes the magnetometer and the inner ring that fixes the magnetometer together perform a 360° attitude change. degrees of freedom in the pose transformation space. Rotate the outer ring rotation axis so that the magnetometer, the middle ring rotation surface, and the inner ring rotation surface can perform 360° attitude transformation together. At the same time, when the outer ring rotation axis is turned, the inner ring rotation axis and the middle ring rotation axis can also freely rotate 360° , so that the magnetometer sensor has a three-degree-of-freedom attitude transformation space, and a vector space with full-degree-of-freedom transformation without dead ends. In the process of attitude transformation, the acquisition device records the magnetic field change value of the magnetometer in real time, so as to collect magnetic field data more comprehensively, efficiently and without interference, and provide more real original error information for error calibration.

Description of drawings

Figure 1 is a diagram of the correspondence between the ideal coordinate system and the actual coordinate system.

Fig. 2 is the overall schematic diagram of the vector magnetometer calibration device;

Fig. 3 is a block diagram of the front view of the vector magnetometer calibration device;

Fig. 4 is a right view structural block diagram of the vector magnetometer calibration device;

Fig. 5 is a top structural block diagram of the vector magnetometer calibration device.

The labels in the attached drawings are: signal line traction clamp 1, signal line traction rod 2, middle ring rotating ring 3, vector magnetometer 4, inner ring rotating ring 5, magnetometer mounting surface 6, dial 7, bearing locking knob 8. Rotating pillar 9, middle ring rotating bearing 10, rotating rod 11, movable handle 12, outer ring locking knob 13, rotating surface 14, outer ring rotating shaft 15, polyethylene base 17, base through hole 18, signal transmission line 19, Scale indicator plate 20, knob 21, locking lever 22, industrial computer 23, fixed disc 24.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the present invention will be further described:

As shown in the figure, this vector (three-component) magnetometer calibration device is made of completely non-magnetic polyethylene material, and the parts are fixed by non-magnetic titanium alloy screws to ensure that the magnetometer is in the calibration experiment. It will not be disturbed by its own magnetic field. It mainly includes a vector magnetometer 4, a base 17, an outer ring rotating device, a middle ring rotating device and an inner ring rotating device, wherein the vector magnetometer 4 is fixed in the center of the inner ring rotating device, and the outer ring rotating device, the middle ring rotating device and the The inner ring rotating device changes the attitude of the vector magnetometer 4, the overall schematic diagram of the vector magnetometer calibration device is shown in Figure 2, wherein the magnetometer 4 is a vector magnetometer that needs to be calibrated, and the industrial computer 23 is a data acquisition device with built-in data acquisition software , when the calibration device rotates, the built-in data acquisition software collects the data of the vector magnetometer 4 in real time. The vector magnetometer 4 is connected to the industrial computer 23 through the signal transmission line 19, and the industrial computer 23 provides a regulated power supply for the vector magnetometer 4, and the length of the signal transmission line 19 can reach 50m, so as to ensure that the industrial computer 23 is far away from the calibration device as far as possible, thereby avoiding industrial control. Machine 23 for magnetic disturbances to the calibration transpose. The outer ring rotation axis scale 16 is marked on the base 17 to indicate the rotation scale of the outer ring, and the scale accuracy is 1°. The base 17 is fixed on the platform through the base through hole 18 to ensure that the entire calibration device will not move arbitrarily during the test.

The outer ring rotating device includes a rotating pillar 9, an outer ring locking knob 13, a rotating surface 14, an outer ring rotating shaft 15 and a fixed disc 24, wherein the rotating pillar 9 is perpendicular to the rotating surface 14, and the two are fixed by non-magnetic titanium alloy screws , there is one each on the left and right of the rotating pillar 9, which is the pillar of the whole calibration device. The rotating surface 14 is arranged in the chute of the base 17 through the outer ring rotating shaft 15, and the outer ring rotating shaft 15 is clamped with the chute of the base 17 through the fixed disk 24, so as to ensure that the rotating surface 14 will not break away from the base 17, and at the same time be able to 360° free rotation, the outer rotation axis is perpendicular to the base 17. The outer ring locking knob 13 plays the role of fixing the rotating surface 14 , when the fixed rotating surface 14 rotates to a certain angle, the rotating surface 14 can be fixed on the base 17 through the outer ring locking knob 13 .

The middle ring rotating device includes a middle ring rotating ring 3, a dial 7, a bearing locking knob 8, a rotating bearing 10, a rotating rod 11 and a movable handle 12, wherein the middle ring rotating ring 3 is installed in the round hole at the top of the rotating pillar 9 through the rotating bearing 10 , the middle ring rotating ring 3 rotates 360° with the middle ring rotating bearing 10 as the middle ring rotating shaft, the middle ring rotating bearing 10 is parallel to the base 17, and can rotate freely on the horizontal plane with the outer ring; the rotating rod 11 is fixed on one end of the middle ring rotating bearing 10 Above, the movable handle 12 is fixed on the other end of the middle ring rotary bearing 10, and the movable handle 12 can freely rotate around its own rotation axis, which is convenient for personnel to operate. By turning the movable handle 12 , the middle ring rotating ring 3 can be driven to rotate around the rotating bearing 10 . The rotating rod 11 has a certain length to ensure the stability and uniformity of the attitude data during the rotation; the dial 7 is rigidly fixed at one end of the middle ring rotating ring 3 and is used to indicate the scale value of the rotation. The bearing locking knob 8 is used to lock the rotating bearing 10 to ensure that the middle ring rotating ring 3 can be fixed at any rotation angle.

The inner ring rotating device includes an inner ring rotating ring 5, a magnetometer mounting surface 6, a scale indicating plate 20, a knob 21, and a locking rod 22. The inner ring rotating ring 5 is installed on the inner side of the middle ring rotating ring 3 by an inner ring rotating bearing. The ring rotation bearing rotates 360° for the rotation axis of the inner ring, and is perpendicular to the middle ring rotation bearing 10. The magnetometer mounting surface 6 is fixed on the inner ring rotation ring 5 by titanium alloy screws, and the center of the magnetometer mounting surface 6 is provided with a In the four installation screw holes of the vector magnetometer 4, the scale indicator plate 20 is used to indicate the angle of rotation of the inner ring rotating ring; the knob 21 is a knob operated by personnel, and the inner ring rotating ring 5 is rotated by rotating the knob 21, thereby driving the magnetic force The vector magnetometer 4 on the instrument installation surface 6 performs attitude transformation. The locking rod 22 is installed in the inner hole of the knob 21. By rotating the locking rod 22, and then through the threaded rotation of the outer wall of the locking rod 22, the locking rod 22 is promoted to move forward or backward, thereby locking or Loosen inner ring swivel ring 5. The signal line traction rod 2 is used to guide the signal line of the magnetometer to the outside of the device, so as to avoid the interruption of the test caused by the signal line winding to the outside of the device during the test; the signal line traction clamp 1 is used to clamp the signal line of the magnetometer, and the auxiliary signal line The external lead, and the signal line traction clamp 1 can be freely installed on the fixed threaded hole on the signal line traction rod 2 according to the test requirements.

The rotation axis of the outer ring and the rotation axis of the middle ring are perpendicular to each other, the rotation axis of the middle ring is perpendicular to the rotation axis of the inner ring, and the vector magnetometer 4 is located at a point where the rotation axis of the outer ring, the rotation axis of the middle ring and the rotation axis of the inner ring intersect to ensure Always at a point in vector space, avoiding disturbing effects of environmental gradients. During the calibration process, each ring can be rotated freely by 360° to ensure that the vector magnetometer can collect magnetic data at any attitude at this point in the vector space, avoiding incomplete calibration data, which is the non-orthogonal degree of the vector magnetometer Calibration provides complete, efficient and accurate hardware support.

The vector magnetometer calibration device can rotate in all directions in the geomagnetic vector space, providing a stable, comprehensive and interference-free data acquisition device for the error correction of the vector magnetometer. The use of non-magnetic polyethylene materials and titanium alloy materials can ensure the purity of the three-component magnetic data without worrying about the introduction of external magnetic interference. It can avoid changing the attitude of the vector magnetometer by manual and other original methods, which may cause dynamic response errors caused by the vibration of the vector magnetometer. The vector magnetometer can be fixed at a point in the vector space, and it will not move even when the attitude of the sensor is changed, thereby avoiding the interference of the magnetic gradient caused by the movement of the vector magnetometer due to manual operation. It has three free steering surfaces, each of which can rotate freely 360°, so as to ensure that the vector magnetometer will not turn to a dead angle when the attitude is changed, and avoid the randomness and accident of manual steering. It can be applied to vector magnetometers of various sizes, and can be flexibly installed according to the size requirements of the vector magnetometer.

In addition to the above-mentioned embodiments, the present invention can also have other implementations, and any technical solution formed by equivalent replacement or equivalent transformation falls within the scope of protection required by the present invention.

Claims (4)

1. a vector magnetic meter calibrating installation, it is characterized in that: mainly comprise vector magnetic meter (4), base (17), outer shroud whirligig, middle ring whirligig and interior ring whirligig, wherein, the centre of ring whirligig is fixed with vector magnetic meter (4), change the attitude of vector magnetic meter (4) by rotation outer shroud whirligig, middle ring whirligig and interior ring whirligig, in the process of rotation, vector magnetic meter (4) data are carried out to acquisition and recording, wherein vector magnetic meter (4) is connected with industrial computer (23) by signal transmssion line (19), base (17) is marked with outer shroud turning axle index dial (16), outer shroud whirligig comprises swinging strut (9), outer shroud locking knob (13), the surfaces of revolution (14), outer shroud turning axle (15) and fixed disc (24), wherein swinging strut (9) is perpendicular to the surfaces of revolution (14), the two is fixed by nonmagnetic Titanium Alloy Screw, swinging strut (9) left and right respectively has one, the surfaces of revolution (14) is arranged in the chute of base (17) by outer shroud turning axle (15), outer shroud turning axle (15) is the chute clamping with base (17) by fixed disc (24), middle ring whirligig comprises middle ring swivel eye (3), index dial (7), bearing locking knob (8), swivel bearing (10), swingle (11) and flexible handle (12), wherein, ring swivel eye (3) is arranged on by swivel bearing (10) in the circular hole on swinging strut (9) top, middle ring swivel eye (3) carries out 360 ° of rotations taking middle ring swivel bearing (10) as middle ring turning axle, middle ring swivel bearing (10) is parallel to base (17), and can on surface level, rotate freely with outer shroud, swingle (11) is fixed on one end of middle ring swivel bearing (10), flexible handle (12) is fixed on the other end of middle ring swivel bearing (10), index dial (7) is rigidly fixed in one end of middle ring swivel eye (3), is used to indicate the scale value of rotation, interior ring whirligig comprises interior ring swivel eye (5), magnetometer installed surface (6), graduation indication dish (20), knob (21) and check lock lever (22), interior ring swivel eye (5) is arranged on the inner side of middle ring swivel eye (3) by interior ring swivel bearing, carry out 360 ° of rotations taking interior ring swivel bearing as interior ring turning axle, and vertical with middle ring swivel bearing (10), magnetometer installed surface (6) is fixed on interior ring swivel eye (5) by Titanium Alloy Screw, and the middle of magnetometer installed surface (6) is provided with the installation screw for vector magnetic meter (4) are installed, graduation indication dish (20) is used to indicate the angle of interior ring swivel eye rotation, rotate interior ring swivel eye (5) by rotation knob (21), and then drive the vector magnetic meter (4) on magnetometer installed surface (6) to carry out posture changing, outer shroud turning axle is mutually vertical with middle ring turning axle, and middle ring turning axle is mutually vertical with interior ring turning axle, and vector magnetic meter (4) is arranged in a bit that outer shroud turning axle, ring turning axle and ring turning axle intersect.

2. vector magnetic meter calibrating installation according to claim 1, is characterized in that: described base (17) is provided with for fixing base plate through holes (18).

3. vector magnetic meter calibrating installation according to claim 1, it is characterized in that: described swinging strut (9) is provided with the signal wire towbar (2) for signal transmssion line (19) being guided to calibrating installation outside, and signal wire towbar (2) is provided with the signal wire haulage clip (1) for clamping signal transmission line (19).

4. vector magnetic meter calibrating installation according to claim 1, it is characterized in that: described check lock lever (22) is arranged in knob (21) endoporus, by rotation lock bar (22), and then promote check lock lever (22) to move forward or move backward by the threads turn of check lock lever (22) outer wall, thereby locking or unclamp interior ring swivel eye (5).