Method and device for calibrating vector magnetometer

Abstract

The invention discloses a method and a device for calibrating a vector magnetometer. The method comprises the following steps: acquiring magnetic induction intensities of a scalar magnetometer and a vector magnetometer to be calibrated which are measured at different angles for multiple times at the same place; calculating scalar magnetic induction intensity according to the vector magnetic induction intensity measured by the vector magnetometer to be calibrated; constructing an error function between the scalar magnetic induction intensity and a measured value of the scalar magnetometer; and performing minimization solution on the error function to obtain an error parameter of the vector magnetometer to be calibrated. According to the method, the magnetic induction intensity of the same place is measured for multiple times by using the scalar magnetometer and the vector magnetometer to be calibrated at different angles, and an equation set is constructed and solved to obtain the system error of the vector magnetometer to be calibrated.

Description

Technical Field

[0001] The present invention relates to the field of magnetic field measurement technology, and in particular to a method for correcting the measurement error of a vector magnetometer when performing geomagnetic measurement, so as to obtain an accurate magnetic induction intensity measurement result. Background Art

[0002] In the prior art, when using a vector magnetometer to measure magnetic induction intensity, there are often multiple system errors, which usually include scale error, offset error and angle error. These errors may come from the discreteness of the instrument itself, installation error, etc. In order to improve the accuracy of magnetic field measurement, these system errors must be effectively corrected.

[0003] Currently, existing methods usually perform corrections by directly calibrating the site or using a known standard field, but these methods are complicated and require expensive equipment for calibration. In addition, some methods cannot effectively obtain systematic errors from measurements at multiple angles, resulting in limited correction effects. Summary of the invention

[0004] In order to solve the calibration problem of the system error of a vector magnetometer, the present invention provides a calibration method and device for a vector magnetometer. By using a scalar magnetometer and a vector magnetometer to be calibrated to measure the magnetic induction intensity of the same location multiple times at different angles, a set of equations is constructed and solved to obtain the system error of the vector magnetometer to be calibrated.

[0005] According to one aspect of the present invention, there is provided a calibration method for a vector magnetometer, comprising: Obtain the magnetic induction intensity of the same location measured multiple times at different angles by a scalar magnetometer and a vector magnetometer to be calibrated; Calculating the scalar magnetic induction intensity according to the vector magnetic induction intensity measured by the vector magnetometer to be calibrated; Constructing an error function between the scalar magnetic induction intensity and the measurement value of the scalar magnetometer; The error function is minimized to obtain the error parameters of the vector magnetometer to be calibrated.

[0006] As a further technical solution, the method further includes: Obtain the scalar magnetometer and the vector magnetometer to be calibrated to measure the magnetic induction intensity of the same location at different angles for at least 9 times.

[0007] As a further technical solution, the method further includes: The modulus of the vector magnetic induction intensity measured by the vector magnetometer to be calibrated is calculated to obtain the corresponding scalar magnetic induction intensity.

[0008] As a further technical solution, the error function constructed is as follows: , in, is the proportional error, is the offset error, is the angle error, is the magnetic induction intensity measured by the scalar magnetometer, , is the scalar magnetic induction intensity calculated using the measurement data of the vector magnetometer to be calibrated.

[0009] As a further technical solution, when minimizing the error function, the error function includes: adjusting the error parameter , and , so that the error is minimized.

[0010] As a further technical solution, when minimizing the error function, the following is also included: Initialize error parameters; Calculating a scalar value corresponding to the vector magnetic induction intensity measured by the vector magnetometer to be calibrated according to the measurement result of the vector magnetometer to be calibrated and the initialization error parameter; An optimization algorithm is used to minimize the error function to obtain the optimal error parameter.

[0011] According to one aspect of the present invention, there is provided a calibration device for a vector magnetometer, comprising: A data acquisition module is used to obtain the magnetic induction intensity of the same location measured multiple times at different angles by a scalar magnetometer and a vector magnetometer to be calibrated; A scalar calculation module, used to calculate the scalar magnetic induction intensity according to the vector magnetic induction intensity measured by the vector magnetometer to be calibrated; An error construction module, used to construct an error function between the scalar magnetic induction intensity and the measurement value of the scalar magnetometer; The error calculation module is used to minimize the error function and obtain the error parameters of the vector magnetometer to be calibrated.

[0012] According to one aspect of the present invention, a calibration device for a vector magnetometer is provided, comprising a scalar magnetometer, a vector magnetometer to be calibrated, and a processing module, wherein the scalar magnetometer is used to provide a scalar magnetic induction intensity, the vector magnetometer to be calibrated is used to provide a vector magnetic induction intensity, and the processing module is used to calibrate the vector magnetometer using the described method.

[0013] According to one aspect of the present invention, a calibration device for a vector magnetometer is provided, comprising a memory and a processor, wherein the memory stores program instructions executed by the processor, and the processor calls the program instructions to execute the steps of the calibration method for the vector magnetometer.

[0014] According to one aspect of the present invention, a non-transitory computer-readable storage medium is provided, wherein the non-transitory computer-readable storage medium stores computer instructions, wherein the computer instructions enable the computer to execute the steps of the vector magnetometer calibration method.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention measures the magnetic induction intensity of the same location multiple times at different angles using a scalar geomagnetometer and a vector geomagnetometer to be calibrated, obtains multiple equations, and obtains the system error of the vector geomagnetometer to be calibrated by solving the equation group. Compared with the prior art, the present invention can quickly and accurately calibrate the system error of the vector geomagnetometer using only a scalar geomagnetometer, saving equipment cost and time cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief introduction is given below to the drawings used in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 A schematic flow chart of a calibration method for a vector magnetometer provided in an embodiment of the present invention.

[0018] Figure 2 A schematic structural diagram of a calibration device for a vector magnetometer provided in an embodiment of the present invention.

[0019] Figure 3 A schematic structural diagram of a calibration device for a vector magnetometer provided in yet another embodiment of the present invention.

[0020] Figure 4 A schematic structural diagram of a calibration device for a vector magnetometer provided in another embodiment of the present invention. DETAILED DESCRIPTION

[0021] In view of the problems that the calibration process of existing vector magnetometers is complicated and the correction effect of some methods is limited, the present invention provides a calibration method for a vector magnetometer. No expensive calibration equipment is required. Only a standard scalar magnetometer (such as a proton magnetometer) is used in combination with mathematical operations to achieve fast and accurate calibration of the vector magnetometer, thereby reducing equipment cost and actual cost.

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In addition, the technical features in the various embodiments or single embodiments provided by the present invention are arbitrarily combined with each other to form a new technical solution. This combination is not restricted by the sequence of steps and / or the structural composition mode, but must be based on the ability of ordinary technicians in this field to achieve. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that this combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0023] See also Figure 1 An embodiment of the present invention provides a calibration method for a vector magnetometer. First, the magnetic induction intensity of a scalar magnetometer and a vector magnetometer to be calibrated is obtained by measuring the magnetic induction intensity of the same location multiple times at different angles. Then, the scalar magnetic induction intensity is calculated according to the vector magnetic induction intensity measured by the vector magnetometer to be calibrated, and an error function between the scalar magnetic induction intensity and the measured value of the scalar magnetometer is constructed. Then, the error function is minimized to obtain the error parameters of the vector magnetometer to be calibrated.

[0024] It should be noted that in the embodiment of the present invention, it is assumed that the relationship between the measured value and the true value is:

[0025] in, is the measurement result of the vector magnetometer; is the actual vector magnetic induction intensity; is the proportional error ( vector); is the offset error ( vector); is the angle error ( vector).

[0026] Assume that the magnetic induction intensity measured by the scalar magnetometer is , then the scalar magnetic induction intensity is the modulus of the magnetic field:

[0027] in, is the real vector magnetic induction intensity, It is the magnetic induction intensity measured by a scalar magnetometer.

[0028] Measurements of vector magnetometers and the true value The error relationship between them can be expressed as:

[0029] By using a scalar magnetometer and a vector magnetometer to be calibrated to measure the magnetic induction intensity of the same location multiple times at different angles, multiple equations are obtained. The system error of the vector magnetometer to be calibrated can be obtained by solving the equation group.

[0030] When collecting data, in order to obtain enough equations to form the equation system, the vector magnetometer to be calibrated and the standard scalar magnetometer are placed on a rotating platform. At different angles, multiple data are measured. The measurement results of the vector magnetometer are: , and its corresponding scalar geomagnetic induction intensity is (Obtained from a scalar magnetometer.) Since there are 9 unknowns, at least 9 measurements are required to solve the following set of equations. To obtain a more accurate and reliable solution, the number of measurements can be increased.

[0031] Assume that in At this angle, the magnetic induction intensity measured by the scalar magnetometer is , the measurement value of the vector magnetometer is , the real vector magnetic induction intensity is , the measurement results of the vector magnetometer contain errors as follows:

[0032] in, is the proportional error, is the offset error, is the angle error.

[0033] The scalar magnetic induction intensity is the modulus of the vector magnetic induction intensity, so:

[0034] The goal of the embodiment of the present invention is to optimize the measurement value of the scalar magnetometer Scalar value calculated from vector magnetometer measurements The difference between.

[0035] Ideally, the scalar magnetic induction intensity at each measurement angle is the modulus of the true magnetic induction intensity. However, due to the existence of errors, the measurement results The calculated scalar and The solution process is to calculate the nine unknowns, namely the scale error, offset error and angle error, so that the measurement results The calculated scalar and Closest.

[0036] The unknowns can be solved using the least squares method, with the goal of minimizing the scalar magnetometer measurement and the scalar magnetic induction intensity calculated by the vector magnetometer The error function can be expressed as:

[0037] in, , which is the scalar value measured by the vector magnetometer.

[0038] In order to minimize the above error function, we need to adjust , and Minimize the error. The following are the specific steps of optimization: Step 1: Calculate the scalar value of the vector magnetic induction intensity based on the measurement results of the vector magnetometer and the optimized error parameters:

[0039] It should be noted that the optimization process is recalculated by substituting the result of the previous iteration, and the optimized error parameter refers to the error parameter obtained in the previous iteration process. Among them, the initial value of the error can be determined based on empirical values ​​(such as the error value of similar equipment); if there is no empirical value, it can be set to no error, that is, the angle error is 0 degrees, the proportional error is set to 1, and the offset error is set to 0.

[0040] Step 2: Minimize the error function:

[0041] By adjusting , and , so that the error function is minimized, thus obtaining the optimal parameters.

[0042] Step 3: Use the least squares method or other optimization algorithms to minimize the error function and obtain the optimal error parameter , and .

[0043] It should be understood that any technology not described in detail in the specification of the present invention may be regarded as conventional technical means or common knowledge in the art.

[0044] The implementation basis of each embodiment of the present invention is to implement programmed processing through a device with a processor function. Therefore, in engineering practice, the technical solutions and functions of each embodiment of the present invention are encapsulated into various modules. Based on this reality, on the basis of the above embodiments, an embodiment of the present invention provides a calibration device for a vector geomagnetometer, which is used to execute the calibration method of the vector geomagnetometer in the above method embodiment.

[0045] See also Figure 2 The device includes: a data acquisition module, used to obtain the magnetic induction intensity of the same place measured multiple times at different angles by a scalar geomagnetometer and a vector geomagnetometer to be calibrated; a scalar calculation module, used to calculate the scalar magnetic induction intensity according to the vector magnetic induction intensity measured by the vector geomagnetometer to be calibrated; an error construction module, used to construct an error function between the scalar magnetic induction intensity and the measurement value of the scalar geomagnetometer; an error calculation module, used to minimize the error function to obtain the error parameter of the vector geomagnetometer to be calibrated.

[0046] The calibration device of the vector magnetometer provided in the embodiment of the present invention is aimed at the calibration problem of the system error of the vector magnetometer. Figure 2 In several modules, the magnetic induction intensity of the same location is measured multiple times at different angles using a scalar magnetometer and a vector magnetometer to be calibrated, and a set of equations is constructed and solved to obtain the system error of the vector magnetometer to be calibrated.

[0047] It should be noted that the device embodiments provided by the present invention are not only used to implement the methods in the above-mentioned method embodiments, but also used to implement the methods in other method embodiments provided by the present invention. The only difference is that the corresponding functional modules are set, and the principles are basically the same as the principles of the above-mentioned device embodiments provided by the present invention. As long as technical personnel in this field refer to the specific technical solutions in other method embodiments on the basis of the above-mentioned device embodiments, obtain the corresponding technical means and the technical solutions composed of these technical means by combining technical features, and on the premise of ensuring the practicality of the technical solutions, they will improve the equipment in the above-mentioned device embodiments to obtain the corresponding device class embodiments for implementing the methods in other method class embodiments.

[0048] Based on the same inventive concept as the above embodiment, the present invention also provides a calibration device for a vector magnetometer, see Figure 3 , including a scalar geomagnetometer, a vector geomagnetometer to be calibrated, and a processing module, the scalar geomagnetometer is used to provide a scalar magnetic induction intensity, the vector geomagnetometer to be calibrated is used to provide a vector magnetic induction intensity, and the processing module is used to calibrate the vector geomagnetometer using the method described.

[0049] Based on the same inventive concept as the above embodiment, the present invention also provides a calibration device for a vector magnetometer, see Figure 4 , including a memory and a processor, the memory stores program instructions executed by the processor, and the processor calls the program instructions to execute the steps of the vector geomagnetometer calibration method.

[0050] Based on the same inventive concept as the above-mentioned embodiment, the embodiment of the present invention also provides a non-transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium stores computer instructions, and the computer instructions enable the computer to execute the steps of the calibration method of the vector magnetometer.

[0051] In summary, the present invention measures the magnetic induction intensity of the same location multiple times at different angles using a scalar geomagnetometer and a vector geomagnetometer to be calibrated, obtains multiple equations, and obtains the system error of the vector geomagnetometer to be calibrated by solving the set of equations. Compared with the prior art, the present invention can quickly and accurately calibrate the system error of the vector geomagnetometer using only a scalar geomagnetometer, saving equipment cost and time cost.

[0052] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices. The flowcharts shown in the accompanying drawings are merely exemplary and do not necessarily include all the contents and operations / steps, nor do they necessarily have to be executed in the order described. For example, some operations / steps may be further decomposed, while some operations / steps may be combined or partially combined, so the actual execution order may change according to the actual situation.

[0053] The terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions, for example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to the steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A method for calibrating a vector magnetometer, characterized in that: include: Obtain the magnetic induction intensity of the same location measured multiple times at different angles by a scalar magnetometer and a vector magnetometer to be calibrated; Calculating the scalar magnetic induction intensity according to the vector magnetic induction intensity measured by the vector magnetometer to be calibrated; Constructing an error function between the scalar magnetic induction intensity and the measurement value of the scalar magnetometer; The error function is minimized to obtain the error parameters of the vector magnetometer to be calibrated.

2. The calibration method of a vector magnetometer according to claim 1, characterized in that: The method further comprises: Obtain the scalar magnetometer and the vector magnetometer to be calibrated to measure the magnetic induction intensity of the same location at different angles for at least 9 times.

3. The calibration method of a vector magnetometer according to claim 1, characterized in that: The method further comprises: The modulus of the vector magnetic induction intensity measured by the vector magnetometer to be calibrated is calculated to obtain the corresponding scalar magnetic induction intensity.

4. The calibration method of a vector magnetometer according to claim 1, characterized in that: The constructed error function is as follows: ， in, is the proportional error, is the offset error, is the angle error, is the magnetic induction intensity measured by the scalar magnetometer, , is the scalar magnetic induction intensity calculated using the measurement data of the vector magnetometer to be calibrated.

5. The calibration method of a vector magnetometer according to claim 1, characterized in that: When minimizing the error function, the error parameter , and , so that the error is minimized.

6. The calibration method of a vector magnetometer according to claim 5, characterized in that: When minimizing the error function, the method further includes: Initialize error parameters; Calculating a scalar value corresponding to the vector magnetic induction intensity measured by the vector magnetometer to be calibrated according to the measurement result of the vector magnetometer to be calibrated and the initialization error parameter; An optimization algorithm is used to minimize the error function to obtain the optimal error parameter.

7. A calibration device for a vector magnetometer, characterized in that: include: A data acquisition module is used to obtain the magnetic induction intensity of the same location measured multiple times at different angles by a scalar magnetometer and a vector magnetometer to be calibrated; A scalar calculation module, used to calculate the scalar magnetic induction intensity according to the vector magnetic induction intensity measured by the vector magnetometer to be calibrated; An error construction module, used to construct an error function between the scalar magnetic induction intensity and the measurement value of the scalar magnetometer; The error calculation module is used to minimize the error function and obtain the error parameters of the vector magnetometer to be calibrated.

8. A calibration device for a vector magnetometer, characterized in that: It comprises a scalar geomagnetometer, a vector geomagnetometer to be calibrated and a processing module, wherein the scalar geomagnetometer is used to provide a scalar magnetic induction intensity, the vector geomagnetometer to be calibrated is used to provide a vector magnetic induction intensity, and the processing module is used to calibrate the vector geomagnetometer by using the method described in any one of claims 1 to 6.

9. A calibration device for a vector magnetometer, characterized in that: It comprises a memory and a processor, wherein the memory stores program instructions executed by the processor, and the processor calls the program instructions to execute the steps of the vector geomagnetometer calibration method according to any one of claims 1 to 6.

10. A non-transitory computer-readable storage medium, characterized in that: The non-transitory computer-readable storage medium stores computer instructions, and the computer instructions enable the computer to execute the steps of the vector magnetometer calibration method according to any one of claims 1 to 6.

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