Error correction method, system and equipment of full-tensor magnetic gradient probe and medium

Abstract

The invention provides an error correction method for a full-tensor magnetic gradient probe. The method comprises the following steps: acquiring chip error data of the full-tensor magnetic gradient probe; the chip error data comprises a full-tensor magnetic gradient of a full-tensor magnetic gradient probe and a gradient of a plane gradiometer; the full-tensor magnetic gradient probe is provided with at least one plane gradiometer; each plane gradiometer is provided with the chip; obtaining an error angle of each plane gradiometer according to the full-tensor magnetic gradient and the gradient of each plane gradiometer; and performing chip angle error correction on the full-tensor magnetic gradient according to the error angle of each plane gradiometer to obtain the corrected full-tensor magnetic gradient. According to the method, the error angle of each plane gradiometer is obtained by comparing the full-tensor magnetic gradient of the full-tensor magnetic gradient probe with the gradient of each plane gradiometer, so that the correction of the angle error of the chip of the full-tensor magnetic gradient probe is completed, and the accuracy of full-tensor magnetic gradient data is improved.

Description

Technical Field

[0001] This application belongs to the technical field of full-tensor magnetic gradient probes, and particularly relates to an error correction method, system, device, and medium for a full-tensor magnetic gradient probe. Background Technique

[0002] The full-tensor magnetic gradient measurement technology is an emerging technology in the field of airborne magnetic survey, which can simultaneously measure the gradient information of the spatial magnetic field vector in three directions, with a total of nine components. Compared with traditional magnetic survey technologies, the full-tensor magnetic gradient measurement has significant advantages, especially suitable for ore body exploration and precise positioning of magnetic targets. This technology can not only provide the direction information of the magnetic field, but also show the characteristics of being insensitive to the attitude change of the flight platform in an environment where the background gradient of the geomagnetic field is much smaller than the magnetic anomaly gradient, making it easier to achieve high-precision measurement.

[0003] The cryogenic superconducting full-tensor magnetic gradient measurement system combines superconducting quantum interference devices (SQUIDs) with airborne magnetic survey technology, and is a culmination of current international frontier technologies. This system replaces the traditional differential method of two sensors with a SQUID-based planar gradiometer, significantly improving the sensitivity and accuracy of magnetic field gradient measurement. Common configurations of cryogenic superconducting full-tensor magnetic gradient probes include regular pentahedron type, regular hexagonal prism type, and cross type. Among them, the regular hexagonal prism type configuration is particularly prominent. Its design can include five independent components (Bxx, Bxy, Bxz, Byy, Byz) of the full tensor of the magnetic gradient field in the output of each planar gradiometer, thus providing good redundancy and reliability for the system.

[0004] The full-tensor magnetic gradient probe with a regular hexagonal frustum configuration consists of six planar gradiometers and a SQUID triaxial magnetometer integrated at the top. Among them, the six planar gradiometers are respectively mounted on the six side surfaces of the module to measure the gradient components, while the triaxial magnetometer at the top is responsible for common-mode compensation. Although this design has high redundancy and potential for high precision, it still faces certain technical challenges in practical applications. During the preparation, packaging, and assembly of the planar gradiometers, mechanical errors will inevitably occur. These errors cause the actual installation position of the chip to deviate from the ideal design position, resulting in the following problems: there are angular errors such as inclination angle, offset angle, and roll angle between the sensitive axis of the chip and the sensitive axis of the module plane. These errors will be superimposed on the output of the gradiometer, thereby reducing the accuracy of the full-tensor magnetic gradient data. Taking one of the planar gradiometers as an example, when there is an error of 1° in the inclination angle, the invariant of the full-tensor magnetic gradient in the measurement result may have a deviation of up to 2.3%. This error has a significant impact on the overall accuracy of the measurement system. Especially in application scenarios that require high sensitivity and high precision, the existence of this error will seriously reduce the accuracy of the full-tensor magnetic gradient data. Summary of the Invention

[0005] This application provides an error correction method, system, device, and medium for a full-tensor magnetic gradient probe, which is used to solve the problem that the existing full-tensor magnetic gradient probe containing planar gradiometers has angular errors such as inclination angle, offset angle, and roll angle between the sensitive axis of the planar gradiometer chip and the sensitive axis of the module plane, thereby reducing the accuracy of the full-tensor magnetic gradient data.

[0006] In the first aspect, this application provides an error correction method for a full-tensor magnetic gradient probe. The method includes: obtaining chip error data of the full-tensor magnetic gradient probe; the chip error data includes the full-tensor magnetic gradient of the full-tensor magnetic gradient probe and the gradient of the planar gradiometer; at least one of the planar gradiometers is provided on the full-tensor magnetic gradient probe; each of the planar gradiometers is provided with the chip; obtaining the error angle of each of the planar gradiometers according to the full-tensor magnetic gradient and the gradient of each of the planar gradiometers; and performing chip angle error correction on the full-tensor magnetic gradient according to the error angle of each of the planar gradiometers to obtain the corrected full-tensor magnetic gradient.

[0007] In one implementation manner of the first aspect, obtaining the chip error data of the full-tensor magnetic gradient probe includes: installing the full-tensor magnetic gradient probe at the central position of the triaxial Maxwell coil; respectively passing a sinusoidal current into the triaxial Maxwell coil by using a signal generator and a power amplifier to obtain the full-tensor magnetic gradient of the full-tensor magnetic gradient probe; and obtaining the gradient output of each planar gradiometer in the triaxial Maxwell coil as the gradient of the planar gradiometer.

[0008] In an implementation of the first aspect, obtaining the error angles of each of the planar gradiometers according to the full tensor magnetic gradient and the gradients of each of the planar gradiometers includes: constructing the error equations of each of the planar gradiometers according to the full tensor magnetic gradient and the gradients of each of the planar gradiometers; respectively solving according to the error equations of each of the planar gradiometers by using the Newton iteration method to obtain the error angles of each of the planar gradiometers; the error angles include dip angle, offset angle and / or roll angle.

[0009] In an implementation of the first aspect, constructing the error equations of each of the planar gradiometers according to the full tensor magnetic gradient and the gradients of each of the planar gradiometers includes: obtaining the vector parameters of each of the planar gradiometers; the vector parameters include baseline vector and plane normal vector; constructing the error equations of each of the planar gradiometers according to the baseline vector and plane normal vector of each of the planar gradiometers, the full tensor magnetic gradient and the gradients of each of the planar gradiometers.

[0010] In an implementation of the first aspect, constructing the error equations of each of the planar gradiometers according to the baseline vector and plane normal vector of each of the planar gradiometers, the full tensor magnetic gradient and the gradients of each of the planar gradiometers includes: , where \(g_{ij}=[g_{i1},g_{i2},g_{i3}]\) is the gradient value output by the \(i\)-th SQUID planar gradiometer, \(G_1\) is the full tensor magnetic gradient of the full tensor magnetic gradient probe, is the baseline vector from the center of the lower pickup loop to the center of the upper pickup loop of the \(i\)-th planar gradiometer, is the plane normal vector of the \(i\)-th planar gradiometer, \(\beta\) 1i , \(\beta\) 2i , \(\beta\) 3i are respectively the offset angle, dip angle and roll angle of the \(i\)-th planar gradiometer, and \(L_i\) is the baseline length of the \(i\)-th planar gradiometer.

[0011] In an implementation of the first aspect, respectively solving according to the error equations of each of the planar gradiometers by using the Newton iteration method to obtain the error angles of each of the planar gradiometers includes: obtaining the initial angle data of each of the planar gradiometers; calculating and obtaining the target equations of each of the planar gradiometers according to the initial angle data of each of the planar gradiometers and the error equations of each of the planar gradiometers; calculating and obtaining the corresponding Jacobian matrix according to the target equations of each of the planar gradiometers; calculating and obtaining the next error angle according to the target equations and Jacobian matrix of each of the planar gradiometers; performing iterative calculation until the target equations of each of the planar gradiometers converge, and taking the error angle at this time as the error angle of each of the planar gradiometers.

[0012] In an implementation of the first aspect, chip angle error correction is performed on the full tensor magnetic gradient according to the error angles of the plane gradiometers, and obtaining the corrected full tensor magnetic gradient includes: calculating and obtaining the error angle functions of the plane gradiometers according to the error angles of the plane gradiometers; performing chip angle error correction calculation according to the error angle functions of the plane gradiometers and the gradients of the plane gradiometers to obtain the corrected full tensor magnetic gradient.

[0013] In a second aspect, the present application provides an error correction system for a full tensor magnetic gradient probe. The system includes: an acquisition module configured to acquire chip error data of the full tensor magnetic gradient probe; the chip error data includes the full tensor magnetic gradient of the full tensor magnetic gradient probe and the gradients of the plane gradiometers; at least one of the plane gradiometers is provided on the full tensor magnetic gradient probe; each of the plane gradiometers is provided with the chip; a calculation module configured to obtain the error angles of the plane gradiometers according to the full tensor magnetic gradient and the gradients of the plane gradiometers; a correction module configured to perform chip angle error correction on the full tensor magnetic gradient according to the error angles of the plane gradiometers to obtain the corrected full tensor magnetic gradient.

[0014] In a third aspect, the present application provides an electronic device. The electronic device includes: a processor and a memory; the memory is configured to store a computer program; the processor is configured to execute the computer program stored in the memory so that the electronic device executes the error correction method for the full tensor magnetic gradient probe as described above.

[0015] In a fourth aspect, the present application provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by an electronic device, the error correction method for the full tensor magnetic gradient probe as described above is implemented.

[0016] As described above, an error correction method, system, device and medium for a full tensor magnetic gradient probe according to the present application have the following beneficial effects:

[0017] This application obtains the chip error data of the full tensor magnetic gradient probe; the chip error data includes the full tensor magnetic gradient of the full tensor magnetic gradient probe and the gradient of the planar gradiometer; at least one of the planar gradiometers is provided on the full tensor magnetic gradient probe; each of the planar gradiometers is provided with the chip; the error angle of each of the planar gradiometers is obtained according to the full tensor magnetic gradient and the gradients of the respective planar gradiometers; the chip angle error of the full tensor magnetic gradient is corrected according to the error angles of the respective planar gradiometers, and the corrected full tensor magnetic gradient is obtained. By using the method of comparing the full tensor magnetic gradient of the full tensor magnetic gradient probe with the gradients of each planar gradiometer, the error angles of each planar gradiometer are respectively obtained, thereby completing the correction of the chip angle error of the full tensor magnetic gradient probe. The advantage of this application compared with the traditional method is that the magnetic field generated by the three-axis Maxwell coil is more uniform than the magnetic field generated by the dipole current, reducing its volume effect, and thus improving the correction accuracy of the chip angle error.

[0018] This application respectively obtains the error angles of each planar gradiometer by using the method of comparing the full tensor magnetic gradient of the full tensor magnetic gradient probe with the gradients of each planar gradiometer. Since there is no need to solve the error parameters during the movement like the traditional method, the magnetic interference caused by the movement is avoided, which affects the error correction result. Brief Description of the Drawings

[0019] Figure 1 It shows a schematic structural diagram of the product device of the full tensor magnetic gradient probe in the shape of a regular hexagonal frustum described in the embodiment of this application.

[0020] Figure 2 It shows a schematic flowchart of the error correction method of the full tensor magnetic gradient probe described in the embodiment of this application.

[0021] Figure 3 It shows a schematic diagram of the position of the cryogenic superconducting full tensor magnetic gradient probe in the three-dimensional Maxwell coil described in the embodiment of this application.

[0022] Figure 4 It shows a schematic diagram of the three installation angle errors of the SQUID planar gradiometer described in the embodiment of this application.

[0023] Figure 5 It shows a schematic flowchart of the error correction method of the full tensor magnetic gradient probe described in the embodiment of this application.

[0024] Figure 6 It shows a schematic flowchart of the Newton iteration for solving the error angle described in the embodiment of this application.

[0025] Figure 7It shows a schematic structural diagram of the error correction system of the full tensor magnetic gradient probe described in the embodiments of the present application.

[0026] Figure 8 It shows a schematic structural diagram of the electronic device described in the embodiments of the present application.

[0027] Description of component numbers

[0028] 11 Triaxial magnetometer

[0029] 12 Planar gradiometer

[0030] 3 Error correction system of the full tensor magnetic gradient probe

[0031] 31 Acquisition module

[0032] 32 Calculation module

[0033] 33 Correction module

[0034] 4 Electronic device

[0035] 41 Memory

[0036] 42 Processor

[0037] Steps S1 to S3 Specific implementation manners

[0038] The following uses specific specific examples to illustrate the implementation manners of the present application. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. The present application can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0039] It should be noted that the drawings provided in the following embodiments only illustrate the basic concept of the present application in a schematic manner. Therefore, only the components related to the present application are shown in the drawings, rather than being drawn according to the number, shape, and size of the components in actual implementation. The types, quantities, and proportions of the components in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0040] The following embodiments of the present application provide a method, system, device, and medium for error correction of a full tensor magnetic gradient probe, which solves the problem that there are angular errors such as inclination angle, offset angle, and roll angle between the sensitive axis of the planar gradiometer chip and the sensitive axis of the module plane in the existing full tensor magnetic gradient probe containing a planar gradiometer, thereby reducing the accuracy of the full tensor magnetic gradient data.

[0041] Figure 1 Shown is a schematic structural diagram of a product device of a full-tensor magnetic gradient probe in the regular hexagonal frustum configuration described in the embodiments of the present application. As Figure 1 shown, this embodiment provides a product device structure of a full-tensor magnetic gradient probe in the regular hexagonal frustum configuration. The full-tensor magnetic gradient probe in the regular hexagonal frustum configuration is composed of six planar gradiometers and a SQUID triaxial magnetometer integrated at the top. Among them, the six planar gradiometers are respectively mounted on the six side faces of the module for measuring gradient components, while the triaxial magnetometer at the top is responsible for common-mode compensation. Although this design has high redundancy and potential for high precision, it still faces certain technical challenges in practical applications. Inevitably, mechanical errors will occur during the preparation, packaging, and assembly of the planar gradiometers. These errors cause the actual installation position of the chip to deviate from the designed ideal position, resulting in the following problems: there are angular errors such as inclination angle, offset angle, and roll angle between the sensitive axis of the chip and the sensitive axis of the module plane. These errors will be superimposed on the output of the gradiometer, thereby reducing the accuracy of the full-tensor magnetic gradient data. Taking one of the planar gradiometers as an example, when there is an error of 1° in the inclination angle, the invariant of the full-tensor magnetic gradient in the measurement result may have a deviation of up to 2.3%. Such errors have a significant impact on the overall accuracy of the measurement system. Especially in application scenarios that require high sensitivity and high precision, error correction becomes a key link.

[0042] Next, the technical solutions in the embodiments of the present application will be described in detail with reference to the accompanying drawings in the embodiments of the present application.

[0043] As Figure 2 shown, this embodiment provides an error correction method for a full-tensor magnetic gradient probe, and the method includes the following steps S1 to S3.

[0044] Step S1, obtain the chip error data of the full-tensor magnetic gradient probe; the chip error data includes the full-tensor magnetic gradient of the full-tensor magnetic gradient probe and the gradient of the planar gradiometer; at least one of the planar gradiometers is provided on the full-tensor magnetic gradient probe; each of the planar gradiometers is provided with the chip.

[0045] Specifically, the full-tensor magnetic gradient probe in the present application is described by taking a cryogenic superconducting full-tensor magnetic gradient probe containing 6 SQUID planar gradiometers as an example. In the cryogenic superconducting full-tensor magnetic gradient probe containing 6 SQUID planar gradiometers in the present application, the angular installation error between the SQUID planar gradiometer and the hexagonal frustum module plane is measured.

[0046] In an embodiment of the present application, obtaining the chip error data of the full-tensor magnetic gradient probe includes the following steps S11 to S13.

[0047] Step S11: Install the full-tensor magnetic gradient probe at the central position of the three-axis Maxwell coil.

[0048] Step S12: Apply sinusoidal currents to the three-axis Maxwell coil respectively using a signal generator and a power amplifier, and obtain the full-tensor magnetic gradient of the full-tensor magnetic gradient probe.

[0049] Step S13: Obtain the gradient output of each planar gradiometer in the three-axis Maxwell coil as the gradient of the planar gradiometer.

[0050] Specifically, Figure 3 It shows a schematic diagram of the position of the cryogenic superconducting full-tensor magnetic gradient probe described in the embodiment of the present application in the three-dimensional Maxwell coil. Figure 4 It shows schematic diagrams of the installation angle errors of the three SQUID planar gradiometers described in the embodiment of the present application. As Figure 3-4 shown, in the present application, the cryogenic superconducting full-tensor magnetic gradient probe containing 6 SQUID planar gradiometers is installed at the central position of the three-axis Maxwell coil. Among them, in the coordinate system o-XYZ of the cryogenic superconducting full-tensor magnetic gradient probe, the six planar coordinate systems of the hexagonal prism are respectively p i -X i Y i Z i (i = 1 to 6), the planar coordinate systems of the i-th SQUID planar gradiometer are respectively pi-X i ’Y i ’Z i ’(i = 1 to 6). The normal direction of the sensitive axis of the pickup loop of the i-th SQUID planar gradiometer is parallel to Z i ’, and the baseline vector directions of the two pickup loops are parallel to X i ’. The tilt angle of the hexagonal prism module is α, and the angles between the planes where the SQUID planar gradiometers are located and the X-axis are β1, β2, and β3 are respectively the offset angle, tilt angle, and roll angle of the SQUID planar gradiometer.

[0051] More specifically, in the present application, sinusoidal currents are first applied to the three axes of the three-axis Maxwell coil respectively using a signal generator and a power amplifier to obtain a coefficient matrix G1 composed of three full-tensor magnetic gradients [Bxxi, Bxyi, Bxzi, Byyi, Byzi] with known parameters (as shown in formula (1)).

[0052]

[0053] Among them, k represents the gradient constant, for example, k = 0.83; μ0 represents the vacuum magnetic permeability, for example, μ0 = 4π×10 -7; a represents the side length of the coil, for example, a = 3m; N represents the number of turns of the coil, for example, N = 19 turns; I represents the input current of the coil, for example, I = 3A.

[0054] Secondly, obtain the gradient outputs [g1i, g2i, g3i, g4i, g5i, g6i] of six SQUID planar gradiometers in the three-axis Maxwell coil to form the measurement gradient value matrix G2 (as shown in formula (2)).

[0055] G2 = [g11, g21, g31, g41, g51, g61,..., g1j, g2j, g3j, g4j, g5j, g6j] j = 1, 2, 3 Formula (2)

[0056] Step S2: Obtain the error angles of each of the planar gradiometers according to the full tensor magnetic gradient and the gradients of each of the planar gradiometers.

[0057] In an embodiment of the present application, obtaining the error angles of each of the planar gradiometers according to the full tensor magnetic gradient and the gradients of each of the planar gradiometers includes the following steps S21 to S22.

[0058] Step S21: Construct the error equations of each of the planar gradiometers according to the full tensor magnetic gradient and the gradients of each of the planar gradiometers.

[0059] Step S22: Solve respectively according to the error equations of each of the planar gradiometers by using the Newton iteration method to obtain the error angles of each of the planar gradiometers; the error angles include inclination angles, offset angles, and / or roll angles.

[0060] In an embodiment of the present application, constructing the error equations of each of the planar gradiometers according to the baseline vectors and plane normal vectors of each of the planar gradiometers, the full tensor magnetic gradient, and the gradients of each of the planar gradiometers includes the following steps S211 to S212.

[0061] Step S211: Obtain the vector parameters of each of the planar gradiometers; the vector parameters include baseline vectors and plane normal vectors.

[0062] Step S212: Construct the error equations of each of the planar gradiometers according to the baseline vectors and plane normal vectors of each of the planar gradiometers, the full tensor magnetic gradient, and the gradients of each of the planar gradiometers.

[0063] In an embodiment of the present application, constructing the error equations of each of the planar gradiometers according to the baseline vectors and plane normal vectors of each of the planar gradiometers, the full tensor magnetic gradient, and the gradients of each of the planar gradiometers includes the following formula.

[0064]

[0065] Among them, \(g_{ij} = [g_{i1}, g_{i2}, g_{i3}]\) is the gradient value output by the \(i\)-th SQUID planar gradiometer, and \(G_1\) is the full-tensor magnetic gradient of the full-tensor magnetic gradient probe. is the baseline vector from the center of the lower pickup loop to the center of the upper pickup loop of the \(i\)-th planar gradiometer. is the plane normal vector of the \(i\)-th planar gradiometer, \(\beta\) 1i , \(\beta\) 2i , \(\beta\) 3i are the offset angle, dip angle, and roll angle of the \(i\)-th planar gradiometer respectively, and \(L_i\) is the baseline length of the \(i\)-th planar gradiometer.

[0066] In an embodiment of the present application, according to the error equations of the respective planar gradiometers, the Newton iteration method is used to solve them respectively, and obtaining the error angles of the respective planar gradiometers includes the following steps S221 to S225.

[0067] Step S221: Obtain the initialization angle data of the respective planar gradiometers.

[0068] Step S222: Calculate and obtain the target equations of the respective planar gradiometers according to the initialization angle data of the respective planar gradiometers and the error equations of the respective planar gradiometers.

[0069] Step S223: Calculate and obtain the corresponding Jacobian matrix according to the target equations of the respective planar gradiometers.

[0070] Step S224: Calculate and obtain the next error angle according to the target equations and the Jacobian matrix of the respective planar gradiometers.

[0071] Step S225: Perform iterative calculation until the target equations of the respective planar gradiometers converge, and use the error angle at this time as the error angle of the respective planar gradiometers.

[0072] Specifically, Figure 5 shows a schematic flow chart of the error correction method of the full-tensor magnetic gradient probe described in the embodiment of the present application. Figure 6 shows a schematic flow chart of the Newton iteration for solving the error angle in the embodiment of the present application. As Figure 5-6 shown, the present application first constructs a non-linear equation about the angle error \([\beta\) 1i , \(\beta\) 2i , \(\beta\) 3i by using the full-tensor magnetic gradient matrix \(G_1\) of the obtained three-dimensional Maxwell coil and the measured gradient value matrix \(G_2\) output by the \(i\)-th SQUID planar gradiometer. \(\beta\) 1i is the rotation angle of the \(i\)-th SQUID planar gradiometer counterclockwise around the plane coordinate system \(Z\) i , and \(\beta\) 2i is the rotation angle of the \(i\)-th SQUID planar gradiometer around the plane coordinate system \(Y\)i Counterclockwise rotation angle, β 3i is the counterclockwise rotation angle of the i-th SQUID planar gradiometer around the X-axis of the planar coordinate system i Then, obtain the baseline vector of the i-th SQUID planar gradiometer after rotation by the angular error and the plane normal vector Among them, the baseline vector of the i-th SQUID planar gradiometer is parallel to the direction of the rotated planar coordinate system X i ’, and the normal vector of the i-th SQUID planar gradiometer is parallel to the direction of the rotated planar coordinate system Z i ’. Among them, the baseline vector of the i-th SQUID planar gradiometer is obtained by calculation using formula (3), and the plane normal vector of the i-th SQUID planar gradiometer is obtained by calculation using formula (4).

[0073]

[0074] Among them, β 1i , β 2i , β 3i are respectively the offset angle, inclination angle, and roll angle of the i-th SQUID planar gradiometer.

[0075] Taking the first SQUID planar gradiometer as an example, the specific construction method of the error equation is shown in the following formula (5).

[0076]

[0077] Among them, g1j = [g11, g12, g13] is the gradient value output by the first SQUID planar gradiometer, G1 is the full tensor magnetic gradient value after applying sinusoidal currents to the three-axis Maxwell coils on the three axes, is the baseline vector from the center of the lower pickup loop to the center of the upper pickup loop of the first SQUID planar gradiometer, is the plane normal vector of the first SQUID planar gradiometer, β 11 , β 21 , β 31 are respectively the offset angle, inclination angle, and roll angle of the first SQUID planar gradiometer, and L1 is the baseline length of the first planar gradiometer.

[0078] Then, construct the full tensor magnetic gradient matrix G1 of the three-dimensional Maxwell coil and the gradient value g1 output by the first SQUID planar gradiometer with respect to β 11 , β 21 , β 31The non - linear equation, and the construction formula of the non - linear equation is shown in the following formula (6).

[0079]

[0080] Wherein, represents the baseline vector of the first SQUID planar gradiometer, represents the plane normal vector of the first SQUID planar gradiometer, [x11, x21, x31, x41, x51] represents the non - linear function of the first SQUID planar gradiometer related to β1, β2, β3, g11 represents the output of the first planar gradiometer that applies a sinusoidal current to the X - axis of the three - dimensional Maxwell coil, g12 represents the output of the first planar gradiometer that applies a sinusoidal current to the Y - axis of the three - dimensional Maxwell coil, and g13 represents the output of the first planar gradiometer that applies a sinusoidal current to the Z - axis of the three - dimensional Maxwell coil. g11(β) represents the theoretical calculated value of the first planar gradiometer that applies a sinusoidal current to the X - axis of the three - dimensional Maxwell coil, g12(β) represents the theoretical calculated value of the first planar gradiometer that applies a sinusoidal current to the Y - axis of the three - dimensional Maxwell coil, and g13(β) represents the theoretical calculated value of the first planar gradiometer that applies a sinusoidal current to the Z - axis of the three - dimensional Maxwell coil.

[0081] Finally, the Newton - Raphson iteration method is used to solve the inclination angle β1, offset angle β2, and roll angle β3 of the 6 - piece SQUID planar gradiometer, as Figure 6 shown, and the specific iteration process is shown in the following formula (7).

[0082] β k+1 = β k - J -1 (β k )·F(β k ) Formula (7)

[0083]

[0084] Wherein, β k = [β1, β2, β3] is the variable vector, k = 1, 2, F(β k ) = [F1(β k ), F2(β k ), F3(β k )] is the target equation set (shown in formula (8)), J(β k ) is the Jacobian matrix (shown in formula (9)), and J -1 (β k ) is the inverse matrix of the Jacobian matrix.

[0085] First, initialize β k= Initial guess value of [β1, β2, β3], and then calculate F(β k ) and J -1 (β k ) in each iteration and update β k+1 . Finally, stop when F(β k ) or the variable change satisfies the convergence condition, and the convergence condition is shown in the following formula (10).

[0086] ||F(β k )||2 < tol or ||Δβ k ||2 < tol Formula (10)

[0087] where, ||·||2 represents the 2-norm (i.e., Euclidean norm), ||Δβ k || represents the parameter change in the current iteration, and tol represents the tolerance. If one of the above convergence conditions is satisfied, the algorithm terminates and returns the current solution β and the number of iterations.

[0088] Step S3: Perform chip angle error correction on the full tensor magnetic gradient according to the error angles of the plane gradiometers, and obtain the corrected full tensor magnetic gradient.

[0089] In an embodiment of the present application, performing chip angle error correction on the full tensor magnetic gradient according to the error angles of the plane gradiometers and obtaining the corrected full tensor magnetic gradient includes the following steps S31 to S32.

[0090] Step S31: Calculate and obtain the error angle functions of the plane gradiometers according to the error angles of the plane gradiometers.

[0091] Step S32: Perform chip angle error correction calculation according to the error angle functions of the plane gradiometers and the gradients of the plane gradiometers, and obtain the corrected full tensor magnetic gradient.

[0092] Specifically, the present application corrects the chip angle error of the independent components of the magnetic gradient full tensor as follows: The outputs of 6 SQUID plane gradiometers are g1, g2, g3, g4, g5, and g6 respectively, and the five independent components of the magnetic gradient full tensor after chip angle error correction are shown in the following formula (11).

[0093]

[0094] where, [x1i, x2i, x3i, x4i, x5i] represents the β 1i , β 2i , β 3iThe unknown quantity of the angular error (as shown in formula (12)), substitute the angular error value solved in S2 into formula (12) and formula (11) for solution, and obtain the corrected full tensor magnetic gradient G1' = [Bxx, Bxy, Bxz, Byy, Byz].

[0095] In this application, by using the method of comparing the magnetic gradient tensor value with known parameters generated by a three-dimensional Maxwell coil and the actual measurement value of the SQUID planar gradiometer, the planar coordinate systems p of 6 SQUID planar gradiometers are respectively obtained. i -X i Y i Z i And the six planar coordinate systems p of the hexagonal frustum i -X i Y i Z i The angular error between them is obtained, thus completing the correction of the angular error of the low-temperature superconducting full tensor magnetic gradient probe chip. The advantages of the technical solution of this application compared with the traditional method are that on the one hand, the magnetic field generated by the three-axis Maxwell coil is more uniform than the magnetic field generated by the dipole current, reducing its volume effect, so the correction accuracy of the chip angular error is improved; on the other hand, this application does not need to solve the error parameters during the movement like the traditional method, thus avoiding the magnetic interference caused by the movement and affecting the error correction result.

[0096] The protection scope of the error correction method of the full tensor magnetic gradient probe described in the embodiments of this application is not limited to the execution order of the steps listed in this embodiment. Any solution realized by adding or subtracting steps of the prior art and replacing steps according to the principle of this application is included in the protection scope of this application.

[0097] The embodiments of this application also provide an error correction system for a full tensor magnetic gradient probe. The error correction system for the full tensor magnetic gradient probe can implement the error correction method of the full tensor magnetic gradient probe described in this application. However, the implementation devices of the error correction method of the full tensor magnetic gradient probe described in this application include but are not limited to the structure of the error correction system for the full tensor magnetic gradient probe listed in this embodiment. Any structural deformation and replacement of the prior art made according to the principle of this application are included in the protection scope of this application.

[0098] As Figure 7 shown, this embodiment provides an error correction system for a full tensor magnetic gradient probe. The system includes: an acquisition module 31, a calculation module 32, and a correction module 33.

[0099] The obtaining module 31 is configured to obtain chip error data of the full-tensor magnetic gradient probe; the chip error data includes the full-tensor magnetic gradient of the full-tensor magnetic gradient probe and the gradients of the planar gradiometers; at least one of the planar gradiometers is provided on the full-tensor magnetic gradient probe; each of the planar gradiometers is provided with the chip;

[0100] The calculating module 32 is configured to obtain the error angles of the respective planar gradiometers according to the full-tensor magnetic gradient and the gradients of the respective planar gradiometers;

[0101] The correcting module 33 is configured to perform chip angle error correction on the full-tensor magnetic gradient according to the error angles of the respective planar gradiometers, and obtain the corrected full-tensor magnetic gradient.

[0102] It should be noted that the functions or operations of the obtaining module 31, the calculating module 32, and the correcting module 33 described in the embodiments of the present disclosure correspond one by one to the steps in the above-described data transmission method for the bus, and thus will not be elaborated herein.

[0103] In several embodiments provided in the present application, it should be understood that the disclosed system, apparatus, or method may be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For example, the division of modules / units is only a logical function division, and there may be other division methods in actual implementation. For example, multiple modules or units may be combined or integrated into another system, or some features may be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other may be through some interfaces, and the indirect couplings or communication connections of devices or modules or units may be in electrical, mechanical, or other forms.

[0104] The modules / units described as separate components may or may not be physically separated, and the components shown as modules / units may or may not be physical modules, that is, they may be located in one place, or may be distributed to multiple network units. Some or all of the modules / units may be selected according to actual needs to achieve the purpose of the embodiments of the present application. For example, in each embodiment of the present application, the respective functional modules / units may be integrated in one processing module, or each module / unit may exist physically separately, or two or more modules / units may be integrated in one module / unit.

[0105] Those of ordinary skill in the art should further realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of this application.

[0106] As Figure 8 shown, this embodiment provides an electronic device, and the electronic device 4 includes: a memory 41 and a processor 42;

[0107] The memory 41 is configured to store a computer program;

[0108] The processor 42 is configured to execute the computer program stored in the memory 41 so that the electronic device 4 executes the error correction method of the full tensor magnetic gradient probe as described above.

[0109] The embodiments of this application also provide a computer-readable storage medium. Those of ordinary skill in the art can understand that all or part of the steps in the method for implementing the above embodiments can be completed by instructing a processor through a program, and the program can be stored in a computer-readable storage medium. The storage medium is a non-transitory medium, such as random access memory, read-only memory, flash memory, hard disk, solid-state drive, magnetic tape, floppy disk, optical disc, and any combination thereof. The above storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or a data center integrating one or more available media. The available medium can be a magnetic medium (such as a floppy disk, hard disk, magnetic tape), an optical medium (such as a digital video disc (DVD)), or a semiconductor medium (such as a solid-state disk (SSD)), etc.

[0110] Embodiments of the present application may further provide a computer program product, which includes one or more computer instructions. When the computer instructions are loaded and executed on a computing device, the processes or functions according to the embodiments of the present application are generated in whole or in part. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website, computer, or data center to another website, computer, or data center in a wired manner (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or a wireless manner (such as infrared, wireless, microwave, etc.).

[0111] When the computer program product is executed by a computer, the computer executes the method described in the foregoing method embodiments. The computer program product may be a software installation package. In the case where the foregoing method needs to be used, the computer program product may be downloaded and executed on the computer.

[0112] In summary, an error correction method, system, device, and medium for a full-tensor magnetic gradient probe according to the present application have the following beneficial effects:

[0113] The present application obtains chip error data of a full-tensor magnetic gradient probe; the chip error data includes the full-tensor magnetic gradient of the full-tensor magnetic gradient probe and the gradient of a planar gradiometer; at least one of the planar gradiometers is provided on the full-tensor magnetic gradient probe; each of the planar gradiometers is provided with the chip; the error angle of each of the planar gradiometers is obtained according to the full-tensor magnetic gradient and the gradients of each of the planar gradiometers; the chip angle error of the full-tensor magnetic gradient is corrected according to the error angles of each of the planar gradiometers to obtain a corrected full-tensor magnetic gradient. By using the method of comparing the full-tensor magnetic gradient of the full-tensor magnetic gradient probe with the gradients of each planar gradiometer, the error angles of each planar gradiometer are obtained respectively, thereby completing the correction of the chip angle error of the full-tensor magnetic gradient probe. The advantage of the present application over the traditional method is that the magnetic field generated by the three-axis Maxwell coil is more uniform than the magnetic field generated by the dipole current, reducing its volume effect, and thus improving the correction accuracy of the chip angle error.

[0114] The present application obtains the error angles of each planar gradiometer respectively by using the method of comparing the full-tensor magnetic gradient of the full-tensor magnetic gradient probe with the gradients of each planar gradiometer. Since there is no need to solve the error parameters during the movement as in the traditional method, the magnetic interference generated by the movement is avoided, which affects the error correction result.

[0115] The descriptions of the processes or structures corresponding to the above-mentioned respective drawings each have their own focuses. For parts not detailed in a certain process or structure, reference may be made to the relevant descriptions of other processes or structures.

[0116] The above embodiments are only illustrative of the principles and effects of the present application and are not intended to limit the present application. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present application should still be covered by the claims of the present application.

Claims

1. A method for error correction of a full tensor magnetic gradient probe, characterized in that: The method comprises: Acquire chip error data of a full tensor magnetic gradient probe; the chip error data includes the full tensor magnetic gradient of the full tensor magnetic gradient probe and the gradient of a planar gradiometer; the full tensor magnetic gradient probe is provided with at least one planar gradiometer; each planar gradiometer is provided with the chip; Acquire the error angle of each of the planar gradiometers according to the full tensor magnetic gradient and the gradient of each of the planar gradiometers; The chip angle error of the full tensor magnetic gradient is corrected according to the error angle of each planar gradiometer to obtain the corrected full tensor magnetic gradient.

2. The error correction method of the full tensor magnetic gradient probe according to claim 1, characterized in that: Obtaining chip error data for full tensor magnetic gradient probes includes: Installing the full tensor magnetic gradient probe at the center of the three-axis Maxwell coil; Using a signal generator and a power amplifier to respectively pass a sinusoidal current into the three-axis Maxwell coil to obtain a full tensor magnetic gradient of a full tensor magnetic gradient probe; The gradient output of each planar gradiometer in the three-axis Maxwell coil is obtained as the gradient of the planar gradiometer.

3. The error correction method of the full tensor magnetic gradient probe according to claim 1, characterized in that: Obtaining the error angle of each of the planar gradiometers according to the full tensor magnetic gradient and the gradient of each of the planar gradiometers comprises: Constructing an error equation of each of the planar gradiometers according to the full tensor magnetic gradient and the gradient of each of the planar gradiometers; The error equations of the planar gradiometers are solved respectively by using the Newton iteration method to obtain the error angles of the planar gradiometers; the error angles include the inclination angle, the offset angle and / or the rollover angle.

4. The error correction method of the full tensor magnetic gradient probe according to claim 3, characterized in that: Constructing the error equation of each planar gradiometer according to the full tensor magnetic gradient and the gradient of each planar gradiometer comprises: Obtaining vector parameters of each of the plane gradiometers; the vector parameters include a baseline vector and a plane normal vector; The error equation of each planar gradiometer is constructed according to the baseline vector and the plane normal vector of each planar gradiometer, the full tensor magnetic gradient and the gradient of each planar gradiometer.

5. The error correction method for a full tensor magnetic gradient probe according to claim 4, characterized in that: Constructing the error equation of each of the planar gradiometers according to the baseline vector and the plane normal vector of each of the planar gradiometers, the full tensor magnetic gradient and the gradient of each of the planar gradiometers comprises: Among them, gij = [gi1, gi2, gi3] is the gradient value output by the i-th SQUID planar gradiometer, G1 is the full tensor magnetic gradient of the full tensor magnetic gradient probe, is the baseline vector from the center of the lower pick-up ring of the i-th planar gradiometer to the center of the upper pick-up ring, is the plane normal vector of the i-th plane gradiometer, β 1i ,β 2i ,β 3i are the offset angle, inclination angle and rollover angle of the i-th plane gradiometer respectively, and Li is the baseline length of the i-th plane gradiometer.

6. The error correction method for a full tensor magnetic gradient probe according to claim 3, characterized in that: The error equations of the planar gradiometers are solved respectively by using the Newton iteration method to obtain the error angles of the planar gradiometers, including: Obtaining initialization angle data of each of the planar gradiometers; Obtaining a target equation of each of the plane gradiometers by calculation according to the initialization angle data of each of the plane gradiometers and the error equation of each of the plane gradiometers; Calculate and obtain the corresponding Jacobian matrix according to the target equation of each plane gradiometer; Obtain the next error angle according to the target equation and Jacobian matrix of each of the plane gradiometers; Iterate the calculation until the target equation of each plane gradiometer converges, and use the error angle at this time as the error angle of each plane gradiometer.

7. The error correction method of the full tensor magnetic gradient probe according to claim 1, characterized in that: Performing chip angle error correction on the full tensor magnetic gradient according to the error angle of each planar gradiometer to obtain the corrected full tensor magnetic gradient includes: Obtaining an error angle function of each of the plane gradiometers according to the error angle calculation of each of the plane gradiometers; A chip angle error correction calculation is performed according to the error angle function of the planar gradiometer and the gradient of each planar gradiometer to obtain a corrected full tensor magnetic gradient.

8. An error correction system for a full tensor magnetic gradient probe, characterized in that: The system comprises: An acquisition module is configured to acquire chip error data of a full tensor magnetic gradient probe; the chip error data includes a full tensor magnetic gradient of the full tensor magnetic gradient probe and a gradient of a planar gradiometer; the full tensor magnetic gradient probe is provided with at least one planar gradiometer; each planar gradiometer is provided with the chip; A calculation module, configured to obtain an error angle of each of the planar gradiometers according to the full tensor magnetic gradient and the gradient of each of the planar gradiometers; The correction module is configured to perform chip angle error correction on the full tensor magnetic gradient according to the error angle of each of the planar gradiometers to obtain a corrected full tensor magnetic gradient.

9. An electronic device, characterized in that: The electronic device comprises: a processor and a memory; The memory is configured to store a computer program; The processor is configured to execute the computer program stored in the memory so as to enable the electronic device to perform the error correction method for the full tensor magnetic gradient probe according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by an electronic device, the error correction method for a full tensor magnetic gradient probe according to any one of claims 1 to 7 is implemented.

Images