Calibration method and device for a vector magnetometer

Abstract

The application discloses a calibration method and device of a vector geomagnetic meter, and the method comprises the following steps: acquiring the magnetic induction intensity of the same place measured by a scalar geomagnetic meter and a vector geomagnetic meter to be calibrated at different angles for multiple times; calculating the scalar magnetic induction intensity according to the vector magnetic induction intensity measured by the vector geomagnetic meter to be calibrated; constructing an error function between the scalar magnetic induction intensity and the measurement value of the scalar geomagnetic meter; and performing minimum solving on the error function to obtain the error parameter of the vector geomagnetic meter to be calibrated. The system error of the vector geomagnetic meter to be calibrated is obtained by constructing an equation group and solving through the magnetic induction intensity of the same place measured by the scalar geomagnetic meter and the vector geomagnetic meter to be calibrated at different angles for multiple times.

Description

Technical Field

[0001] This invention relates to the field of magnetic field measurement technology, and in particular to a method for correcting measurement errors of a vector magnetometer during geomagnetic measurements, thereby obtaining accurate magnetic induction intensity measurement results. Background Technology

[0002] In existing technologies, the measurement of magnetic field intensity using vector magnetometers often encounters various systematic errors, which typically include proportional errors, offset errors, and angular errors. These errors may originate from the inherent discreteness of the instrument itself, installation errors, etc. To improve the accuracy of magnetic field measurements, these systematic errors must be effectively corrected.

[0003] Currently, existing methods typically involve correction through direct calibration of the site or the use of known standard fields. However, these methods are complex and require expensive equipment for calibration. Furthermore, some methods cannot effectively extract systematic errors from measurements at multiple angles, thus limiting the effectiveness of the correction. Summary of the Invention

[0004] To address the calibration problem of systematic errors in vector magnetometers, this invention provides a calibration method and apparatus for vector magnetometers. By repeatedly measuring the magnetic induction intensity at the same location using a scalar magnetometer and a vector magnetometer to be calibrated at different angles, a system of equations is constructed and solved to obtain the systematic error of the vector magnetometer to be calibrated.

[0005] According to one aspect of the present invention, a calibration method for a vector magnetometer is provided, comprising: The magnetic field strength at the same location was measured multiple times at different angles by a scalar magnetometer and a vector magnetometer to be calibrated. Calculate the scalar magnetic induction intensity based on the vector magnetic induction intensity measured by the vector magnetometer to be calibrated; Construct an error function between the scalar magnetic induction intensity and the measured 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 also includes: Obtain at least nine measurements of the magnetic flux density at the same location from different angles using a scalar magnetometer and a vector magnetometer to be calibrated.

[0007] As a further technical solution, the method also includes: Calculate the modulus of the vector magnetic flux density measured by the vector magnetometer to be calibrated, and obtain the corresponding scalar magnetic flux density.

[0008] As a further technical solution, the constructed error function is as follows: , in, For proportional error, This is the offset error. For angular error, The magnetic flux density is measured by a scalar magnetometer. , is the scalar magnetic flux density calculated from the measurement data of the vector magnetometer to be calibrated.

[0009] As a further technical solution, minimizing the error function includes: adjusting the error parameters. , and This minimizes the error.

[0010] As a further technical solution, the process of minimizing the error function further includes: Initialize error parameters; Based on the measurement results and initial error parameters of the vector magnetometer to be calibrated, calculate the scalar value corresponding to the vector magnetic induction intensity measured by the vector magnetometer to be calibrated. The optimal error parameters are obtained by minimizing the error function using an optimization algorithm.

[0011] According to one aspect of the present invention, a calibration apparatus for a vector magnetometer is provided, comprising: The data acquisition module is used to acquire 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. The scalar calculation module is used to calculate the scalar magnetic induction intensity based on the vector magnetic induction intensity measured by the vector magnetometer to be calibrated. An error construction module is used to construct an error function between the scalar magnetic induction intensity and the measured value of the scalar magnetometer; The error calculation module is used to minimize the error function to obtain the error parameters of the vector magnetometer to be calibrated.

[0012] According to one aspect of the present invention, a calibration apparatus 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 method described above.

[0013] According to one aspect of the present invention, a calibration apparatus for a vector magnetometer is provided, comprising a memory and a processor, the memory storing program instructions that are executed by the processor, the processor invoking the program instructions to perform 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, the non-transitory computer-readable storage medium storing computer instructions that cause the computer to perform the steps of the calibration method of the vector magnetometer.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention obtains multiple equations by repeatedly measuring the magnetic induction intensity at the same location from different angles using a scalar magnetometer and a vector magnetometer to be calibrated. The systematic error of the vector magnetometer to be calibrated is then obtained by solving the system of equations. Compared to existing technologies, this invention uses only a scalar magnetometer to quickly and accurately calibrate the systematic error of a vector magnetometer, saving both equipment and time costs. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic flowchart of the calibration method for a vector magnetometer provided in an embodiment of the present invention.

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

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

[0020] Figure 4 A schematic diagram of the structure of a calibration device for a vector magnetometer provided in another embodiment of the present invention. Detailed Implementation

[0021] This invention addresses the problems of complex calibration processes and limited correction effects of existing vector magnetometers by providing a calibration method for vector magnetometers. This method eliminates the need for expensive calibration equipment and uses only a standard scalar magnetometer (such as a proton magnetometer) combined with mathematical calculations to achieve rapid and accurate calibration of the vector magnetometer, thereby reducing equipment and actual costs.

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In addition, the technical features of the various embodiments or individual embodiments provided by the present invention can be arbitrarily combined to form new technical solutions. Such combinations are not bound by the order of steps and / or structural composition patterns, but must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0023] Please see Figure 1 This invention provides a calibration method for a vector magnetometer. First, a scalar magnetometer and a vector magnetometer to be calibrated are used to measure the magnetic flux density at the same location multiple times at different angles. Next, based on the vector magnetic flux density measured by the vector magnetometer to be calibrated, a scalar magnetic flux density is calculated, and an error function between the scalar magnetic flux density 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 this embodiment of the invention, the relationship between the measured value and the true value is assumed to be as follows: , in, These are the measurement results from a vector magnetometer; It is the actual vector magnetic flux density; It is the proportional error ( vector); It is the offset error ( vector); It is angular error ( vector).

[0025] Let the magnetic flux density measured by the scalar magnetometer be... Then the scalar magnetic induction intensity is the modulus of the magnetic field: , in, This represents the actual vector magnetic flux density. The magnetic flux density is measured by a scalar magnetometer.

[0026] Measurements from a vector magnetometer and the true value The error relationship between them can be expressed as: , By measuring the magnetic induction intensity at the same location multiple times at different angles using a scalar magnetometer and a vector magnetometer to be calibrated, multiple equations are obtained. Solving the system of equations yields the systematic error of the vector magnetometer to be calibrated.

[0027] During data acquisition, in order to obtain enough equations to form a system of equations, the vector magnetometer to be calibrated and the standard scalar magnetometer are placed on a rotating platform. Multiple data points were measured at various angles, and the results from the vector magnetometer are as follows: Its corresponding scalar geomagnetic magnetic induction intensity is (Obtained from a scalar magnetometer). Since there are 9 unknowns, at least 9 measurements are required for the subsequent system of equations to have a solution. However, to obtain a more accurate and reliable solution, the number of measurements can be increased.

[0028] Assuming in the first At each angle, the magnetic flux density measured by the scalar magnetometer is: The measurement value of the vector magnetometer is The actual vector magnetic flux density is The measurement results of the vector magnetometer include errors, as shown below: , in, For proportional error, This is the offset error. This represents the angular error.

[0029] The scalar magnetic flux density is the magnitude of the vector magnetic flux density, therefore: .

[0030] The objective of this invention is to optimize the measurements of a scalar magnetometer. Scalar values ​​calculated from measurements by a vector magnetometer The differences between them.

[0031] Ideally, the scalar magnetic flux density at each measurement angle is the modulus of the true magnetic flux density. However, due to the presence of errors, the measurement results... Calculated scalar and They are not consistent. The solution process involves calculating nine unknowns, including proportional error, offset error, and angular error, to arrive at the measurement results. Calculated scalar and The closest.

[0032] The unknowns can be solved using the least squares method, with the goal of minimizing the scalar magnetometer measurements. and the scalar magnetic flux density calculated by a vector magnetometer The error between them. The error function can be expressed as: , in, That is, the scalar value obtained by measuring with a vector magnetometer.

[0033] To minimize the above error function, it is necessary to adjust... , and To minimize the error, the following are the specific steps for optimization:

[0034] Step 1: Based on the measurement results of the vector magnetometer and the optimized error parameters, calculate the scalar value of the vector magnetic induction intensity: .

[0035] It should be noted that the optimization process recalculates by substituting the results of the previous iteration, and the error parameters for optimization refer to the error parameters obtained in the previous iteration. The initial value of the error can be determined based on empirical values ​​(e.g., the error values ​​of similar devices); if no empirical values ​​are available, it can be set to zero error, i.e., the angular error is 0 degrees, the proportional error is 1, and the offset error is 0.

[0036] Step 2: Minimize the error function: , By adjusting , and This minimizes the error function, thus yielding the optimal parameters.

[0037] Step 3: Use the least squares method or other optimization algorithms to minimize the error function and obtain the optimal error parameters. , and .

[0038] It should be understood that any techniques not described in detail in this specification are considered conventional techniques or common knowledge in the field.

[0039] The implementation of the various embodiments of the present invention is based on programmed processing by a device with processor functionality. Therefore, in practical engineering, the technical solutions and functions of the various embodiments of the present invention are encapsulated into various modules. Based on this reality, and building upon the above embodiments, the embodiments of the present invention provide a calibration device for a vector magnetometer, which is used to execute the calibration method for a vector magnetometer in the above method embodiments.

[0040] See Figure 2 The device includes: a data acquisition module for acquiring magnetic induction intensity measured multiple times at the same location by a scalar magnetometer and a vector magnetometer to be calibrated at different angles; a scalar calculation module for calculating a scalar magnetic induction intensity based on the vector magnetic induction intensity measured by the vector magnetometer to be calibrated; an error construction module for constructing an error function between the scalar magnetic induction intensity and the measured value of the scalar magnetometer; and an error calculation module for minimizing the error function to obtain the error parameters of the vector magnetometer to be calibrated.

[0041] The calibration device for a vector magnetometer provided in this embodiment of the invention addresses the calibration problem of systematic errors in vector magnetometers, employing... Figure 2 Several modules in the process are used to construct a system of equations and solve for the systematic error of the vector magnetometer to be calibrated by measuring the magnetic induction intensity at the same location multiple times at different angles using a scalar magnetometer and a vector magnetometer to be calibrated.

[0042] It should be noted that the device embodiments provided by the present invention are used not only to implement the methods in the above method embodiments, but also to implement the methods in other method embodiments provided by the present invention. The only difference is that corresponding functional modules are set. The principle is basically the same as that of the above device embodiments provided by the present invention. As long as those skilled in the art can improve the device in the above device embodiments by referring to the specific technical solutions in other method embodiments, combining technical features to obtain corresponding technical means and technical solutions composed of these technical means, and ensuring the practicality of the technical solutions, they can obtain corresponding device-type embodiments for implementing the methods in other method-type embodiments.

[0043] Based on the same inventive concept as the above embodiments, this embodiment of the invention also provides a calibration device for a vector magnetometer, see [link to documentation]. Figure 3 The system includes a scalar magnetometer, a vector magnetometer to be calibrated, and a processing module. The scalar magnetometer is used to provide scalar magnetic induction intensity, the vector magnetometer to be calibrated is used to provide vector magnetic induction intensity, and the processing module is used to calibrate the vector magnetometer using the method described above.

[0044] Based on the same inventive concept as the above embodiments, this embodiment of the invention also provides a calibration device for a vector magnetometer, see [link to documentation]. Figure 4 It includes a memory and a processor, the memory storing program instructions that are executed by the processor, and the processor calling the program instructions to perform the steps of the calibration method for the vector magnetometer.

[0045] Based on the same inventive concept as the above embodiments, this embodiment of the invention also provides a non-transitory computer-readable storage medium storing computer instructions that cause the computer to execute the steps of the vector magnetometer calibration method.

[0046] In summary, this invention obtains multiple equations by repeatedly measuring the magnetic induction intensity at the same location from different angles using a scalar magnetometer and a vector magnetometer to be calibrated. The systematic error of the vector magnetometer to be calibrated is then obtained by solving the system of equations. Compared to existing technologies, this invention uses only a scalar magnetometer to quickly and accurately calibrate the systematic error of a vector magnetometer, saving both equipment and time costs.

[0047] 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 can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices. The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be decomposed, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0048] The terms “comprising” and “having”, and any variations thereof, in the specification, claims, and accompanying drawings of this invention are intended to cover a non-exclusive inclusion, such as a process, method, system, product, or apparatus that includes a series of steps or units, not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A calibration method for a vector magnetometer, characterized in that, include: The magnetic field strength at the same location is measured multiple times at different angles by a scalar magnetometer and a vector magnetometer to be calibrated, wherein the scalar magnetometer and the vector magnetometer to be calibrated are placed at the same measurement location and rotated synchronously to multiple different angles. Calculate the scalar magnetic induction intensity based on the vector magnetic induction intensity measured by the vector magnetometer to be calibrated; An error function is constructed between the scalar magnetic induction intensity and the measured value of the scalar magnetometer, wherein the error function is the sum of squares of the differences between the measured value of the scalar magnetometer at each measurement angle and the scalar value calculated from the measured value of the vector magnetometer. The error parameters of the vector magnetometer to be calibrated include proportional error, offset error and angular error. The error function is minimized to obtain the proportional error, offset error, and angular error of the vector magnetometer to be calibrated.

2. The calibration method for the vector magnetometer according to claim 1, characterized in that, The method further includes: Obtain at least nine measurements of the magnetic flux density at the same location from different angles using a scalar magnetometer and a vector magnetometer to be calibrated.

3. The calibration method for the vector magnetometer according to claim 1, characterized in that, The method further includes: Calculate the modulus of the vector magnetic flux density measured by the vector magnetometer to be calibrated, and obtain the corresponding scalar magnetic flux density.

4. The calibration method for the vector magnetometer according to claim 1, characterized in that, Minimizing the error function involves adjusting the error parameters to minimize the error.

5. The calibration method for the vector magnetometer according to claim 4, characterized in that, When minimizing the error function, the method further includes: Initialize error parameters; Based on the measurement results and initial error parameters of the vector magnetometer to be calibrated, calculate the scalar value corresponding to the vector magnetic induction intensity measured by the vector magnetometer to be calibrated. The optimal error parameters are obtained by minimizing the error function using an optimization algorithm.

6. A calibration device for a vector magnetometer, characterized in that, include: The data acquisition module is used to acquire 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. The scalar magnetometer and the vector magnetometer to be calibrated are placed at the same measurement location and rotated synchronously to multiple different angles. The scalar calculation module is used to calculate the scalar magnetic induction intensity based on the vector magnetic induction intensity measured by the vector magnetometer to be calibrated. An error construction module is used to construct an error function between the scalar magnetic induction intensity and the measured value of the scalar magnetometer. The error function is the sum of squares of the differences between the measured value of the scalar magnetometer at each measurement angle and the scalar value calculated from the measured value of the vector magnetometer. The error parameters of the vector magnetometer to be calibrated include proportional error, offset error and angular error. The error calculation module is used to minimize the error function and obtain the proportional error, offset error and angular error of the vector magnetometer to be calibrated.

7. A calibration device for a vector magnetometer, characterized in that, The device includes a scalar magnetometer, a vector magnetometer to be calibrated, and a processing module. 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 method described in any one of claims 1-5.

8. A calibration device for a vector magnetometer, characterized in that, It includes a memory and a processor, the memory storing program instructions that are executed by the processor, the processor calling the program instructions to perform the steps of the calibration method for the vector magnetometer according to any one of claims 1-5.

9. A non-transitory computer-readable storage medium, characterized in that, The non-transitory computer-readable storage medium stores computer instructions that cause the computer to perform the steps of the calibration method for the vector magnetometer as described in any one of claims 1-5.

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