Static positioning method and positioning device for magnetic target

Abstract

The invention provides a static positioning method and positioning device for a magnetic target. The static positioning method comprises the following steps: acquiring full-tensor magnetic gradient data of a moving magnetic target at n measurement positions in a preset time period based on the static magnetic target positioning device; selecting one of the measurement positions as the initial position of the magnetic target, solving the measurement positions of the magnetic target based on the initial position and the full tensor invariant, and performing fitting according to the motion trail characteristics of the magnetic target to obtain the minimum mean square error after fitting; changing the initial position of the magnetic target and circularly executing the previous step; and taking the initial position with the optimal minimum mean square error after fitting as a final solution, obtaining the position information of the magnetic target based on the full tensor invariant and the final solution of the initial position, and realizing the positioning of the magnetic target. According to the invention, magnetic target positioning is realized based on full tensor invariants and motion trail constraints, and positioning of a fixed magnetic moment magnetic source can be simply and rapidly realized through a set of measurement processes and test data post-processing; positioning precision is high and cost is low.

Description

Technical Field

[0001] The invention relates to the field of magnetic detection, and in particular to a static positioning method and a positioning device for a magnetic target. Background Art

[0002] The full tensor magnetic gradient describes the rate of change of the magnetic field vector in three-dimensional space, that is, the gradients of the three components of the magnetic field vector in three directions in space. The measurement results of the full tensor magnetic gradient are less affected by the magnetization direction, can reflect the vector magnetic moment information of the target body, and can better invert the field source parameters (azimuth, magnetic moment, etc.). Therefore, the field source can be located and tracked, and the resolution of the magnetic source body can be improved. The measurement and interpretation of the full tensor magnetic gradient is regarded as a major breakthrough in magnetic exploration, and it has important application value in resource exploration, military, archaeology, environment and other fields.

[0003] According to the theory of linear algebra, the full tensor magnetic gradient matrix and its matrix after posture projection are similar matrices, so they have the same eigenvalues, that is, at a certain measurement point, no matter what its posture is, the full tensor magnetic gradient matrix composed of its measurement results has the same real eigenvalue, and three types of geometric invariants can be derived from its eigenvalues ​​and their corresponding eigenvectors, namely, the angle between the magnetic moment of the magnetic source and the position vector can be uniquely represented by the three eigenvalues ​​of the full tensor magnetic gradient matrix, the eigenvector corresponding to the eigenvalue with the smallest absolute value of the full tensor magnetic gradient matrix is ​​perpendicular to the magnetic moment and the position vector, and the unit vectors of the magnetic moment and the position vector can be represented by the eigenvalue of the full tensor magnetic gradient matrix and the eigenvectors corresponding to the remaining two eigenvalues ​​except the one with the smallest absolute value.

[0004] Currently known technologies cannot realize the positioning of a moving magnetic source in a static state using a single full-tensor magnetic gradient measurement device. The total field information of the magnetic source or multiple measurement point information is required to achieve positioning. However, the total field of the magnetic source is difficult to obtain accurately during the actual measurement process due to the fluctuations in the earth's magnetic field. In addition, even if a method of locating a long-distance magnetic source by multi-point measurement in a moving state is adopted, if the distance between multiple measurement points is not enough, the signal-to-noise ratio of the measurement signal is not enough and the positioning cannot be effectively performed. In this case, it is equivalent to a static measurement. For a superconducting full-tensor magnetic gradient measurement device, not only is the cost of the device high, but the SQUID itself is sensitive to motion. If a moving magnetic source can be located in a static state based on a single superconducting full-tensor magnetic gradient measurement device, it has important practical significance.

[0005] Therefore, the currently disclosed magnetic source positioning method based on full tensor invariants cannot effectively realize magnetic source positioning in a static state based on a single full tensor magnetic gradient measurement device. A method that can realize magnetic source positioning in a static state is urgently needed, which is crucial for the strategically significant superconducting magnetic measurement system.

[0006] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present invention and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because these solutions are described in the background technology section of the present invention. Summary of the invention

[0007] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a static positioning method and positioning device for a magnetic target, so as to solve the problem in the prior art that it is impossible to effectively realize magnetic source positioning based on a single full-tensor magnetic gradient measurement device in a static state.

[0008] To achieve the above-mentioned object and other related objects, the present invention provides a static positioning method for a magnetic target, the positioning method for a magnetic target at least comprising:

[0009] 11) obtaining full tensor magnetic gradient data of n measurement positions of a moving magnetic target within a preset time period based on a static magnetic target positioning device, where n is a natural number greater than or equal to 3;

[0010] 12) selecting one of the measurement positions as the initial position of the magnetic target, obtaining the measurement positions of the magnetic target based on the initial position and the full tensor invariant in the full tensor magnetic gradient data, and fitting according to the motion trajectory characteristics of the magnetic target to obtain the minimum mean square error after fitting;

[0011] 13) changing the initial position of the magnetic target and executing step 12) repeatedly until the minimum mean square error corresponding to all initial positions is calculated;

[0012] 14) The initial position with the best minimum mean square error after fitting is taken as the final solution, and the position information of the magnetic target is obtained based on the full tensor invariant and the final solution of the initial position to achieve the positioning of the magnetic target.

[0013] Optionally, in step 11), full tensor gradient data of m measurement positions are obtained, and a threshold of a characteristic value of the full tensor magnetic gradient matrix is ​​set, and full tensor magnetic gradient data whose characteristic value is greater than the threshold is retained to obtain data whose signal-to-noise ratio meets processing requirements; wherein m is a natural number greater than or equal to n.

[0014] Optionally, the initial position of the magnetic target is changed by using a grey wolf algorithm or a region traversal method.

[0015] Optionally, the method for obtaining each measured position of the magnetic target based on the initial position of the magnetic target and the full tensor invariant includes:

[0016] 21) respectively calculating the ratio of the distance from the initial position to the magnetic target positioning device to the distance from each other measurement position to be calculated to the magnetic target positioning device, thereby obtaining the distance from each measurement position of the magnetic target to the magnetic target positioning device;

[0017] 22) a unit vector of the magnetic moment vector, determining the position vector of the magnetic target;

[0018] 23) The position of the magnetic target is obtained based on the distance between the magnetic target positioning device and the corresponding measurement position, and the unit vector of the position vector of the magnetic target.

[0019] More optionally, in step 21), the ratio satisfies:

[0020]

[0021] in, is the ratio of the distance from the initial position to the magnetic target positioning device to the distance from the i-th measured position to be calculated to the magnetic target positioning device, i is a natural number less than or equal to n-1; R0 is the distance from the initial position to the magnetic target positioning device, R i is the distance from the i-th measurement position to the magnetic target positioning device, NT0 is the full tensor invariant of the initial position, NT i is the full tensor invariant at the i-th measurement position.

[0022] More optionally, step 22) comprises:

[0023] 221) obtaining four unit vectors of the position vector of the magnetic target based on the full tensor magnetic gradient data;

[0024] 222) removing two imaginary solutions of the position vector of the magnetic target according to the magnetic moment direction vector whose positive and negative are not determined;

[0025] 223) is used with the aid of actual a priori conditions to determine a unique solution for the unit vector of the position vector of the magnetic target.

[0026] More optionally, in step 221), four unit vectors of the position vector of the magnetic target are calculated based on the following formula:

[0027]

[0028] in, is the unit vector of the position vector of the magnetic target, λ1, λ2, λ3 are the eigenvalues ​​of the full tensor magnetic gradient matrix, and λ2≥λ3≥λ1, |λ1|≥|λ3|, |λ2|≥|λ3|.

[0029] More optionally, in step 222), the virtual solution is removed based on the following formula:

[0030]

[0031] V3·m=0;

[0032]

[0033]

[0034] in, is the unit vector of the magnetic moment vector of the magnetic target, λ1 and λ2 are the eigenvalues ​​of the full tensor magnetic gradient matrix, and λ2≥λ3≥λ1, |λ1|≥|λ3|, |λ2|≥|λ3|; V1 is the eigenvector of the eigenvalue λ1 of the full tensor magnetic gradient matrix, V2 is the eigenvector of the eigenvalue λ2 of the full tensor magnetic gradient matrix, and V3 is the eigenvector corresponding to the eigenvalue λ3 of the full tensor magnetic gradient matrix.

[0035] More optionally, the prior conditions in step 223) include: the approximate direction of the magnetic target.

[0036] Optionally, the method of fitting and obtaining the minimum mean square error in step 12) includes:

[0037] 31) analyzing the motion trajectory of the magnetic target according to a priori conditions and expressing it abstractly using mathematical formulas;

[0038] 32) Based on the least squares or intelligent algorithm, the motion trajectory of the magnetic target is fitted using the mathematical formula to minimize the mean square error;

[0039] 33) According to the fitting results, the minimum mean square error after fitting is obtained.

[0040] More optionally, the prior condition in step 31) includes the type of the magnetic target.

[0041] More optionally, when the motion trajectory of the magnetic target is a straight line in space, the mathematical formula satisfies:

[0042]

[0043] Among them, x, y, z are the positions of the magnetic target, x0, y0, z0 are the initial positions of the magnetic target, and P, Q, H are the direction vectors of the spatial straight line abstracted from the motion trajectory.

[0044] More optionally, when the motion trajectory of the magnetic target is a straight line in a plane, the mathematical formula satisfies:

[0045]

[0046] Wherein, x, y, z are the positions of the magnetic target, and a, b, c are the parameters of the plane straight line abstracted from the motion trajectory.

[0047] More optionally, the mean square error satisfies:

[0048]

[0049] Among them, H0 is the mean square error, f xi 、f yi 、f zi is the magnetic target position solved according to the set initial magnetic target position (x0, y0, z0), k xi , k yi , k zi is the spatial position after fitting according to the mathematical formula.

[0050] To achieve the above-mentioned object and other related objects, the present invention also provides a magnetic target positioning device, which at least comprises: a bracket, a full tensor magnetic gradient measurement component and a measurement and control component;

[0051] The bracket is used to carry the full tensor magnetic gradient measurement component and the measurement and control component;

[0052] The full tensor magnetic gradient measurement component is used to detect magnetic targets;

[0053] The measurement and control component is electrically connected to the full tensor magnetic gradient measurement component, and is used to provide a test signal to the full tensor magnetic gradient measurement component, and to read and process the data collected by the full tensor magnetic gradient measurement component.

[0054] Optionally, the magnetic target positioning device further comprises a locator, which is disposed on the bracket and is used to obtain the longitude, latitude and / or altitude information of the full tensor magnetic gradient measurement component.

[0055] As described above, the static positioning method and positioning device of the magnetic target of the present invention have the following beneficial effects:

[0056] The method of the present invention realizes magnetic target positioning based on full tensor invariants and motion trajectory constraints. The device constructed by this method can quickly realize the positioning of a fixed magnetic moment magnetic source through a set of measurement processes and test data post-processing. The present invention can realize magnetic source positioning in a static state, with high positioning accuracy and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 Shown is a schematic flow chart of the static positioning method of a magnetic target of the present invention.

[0058] Figure 2 Shown is a schematic diagram of the four combinations of magnetic moment vector and position vector.

[0059] Figure 3 Shown is a schematic diagram of the principle of the static positioning method of a magnetic target of the present invention.

[0060] Figure 4 Shown is a schematic diagram of the structure of the system in which the magnetic target positioning device of the present invention is located.

[0061] Component number description

[0062] 1 Full tensor magnetic gradient measurement component

[0063] 2 Bracket

[0064] 3 Measurement and control components

[0065] 4 Locator

[0066] 5 Magnetic Target

[0067] 6 Ground DETAILED DESCRIPTION

[0068] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0069] See also Figure 1 to Figure 4 It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0070] For the problem of magnetic source location, a magnetic source location method based on full tensor geometric invariants is: first, the eigenvalues ​​and total fields of the full tensor magnetic gradient matrix are used to solve the distance of the magnetic dipole relative to the measurement point and the magnetic moment modulus, and then the geometric invariants are used to solve the position of the magnetic dipole and the unit vector of the magnetic moment vector. Finally, after removing the virtual solutions of the magnetic dipole position and magnetic moment vector, the position of the magnetic source can be obtained by synthesizing their unit vectors and moduli. This method cannot locate the magnetic source in real time when the total field information of the magnetic source is unknown, and it requires multi-point measurement, that is, it is impossible to locate the magnetic source in a static state.

[0071] Another static positioning method of magnetic source realizes real-time positioning of magnetic source in motion based on full tensor invariant, under the premise of knowing the initial position of magnetic source or obtaining the initial position of magnetic source by moving full tensor magnetic gradient measuring device. Although this method provides a method for realizing real-time positioning of magnetic target in static state, it requires the initial position of magnetic target.

[0072] Based on the above problems, the present invention provides a static positioning method for a magnetic target, which uses the motion trajectory of the magnetic target as a constraint condition to solve the positioning problem of the magnetic target and even improve the positioning accuracy of the magnetic target; Figure 1 As shown, the magnetic target positioning method includes:

[0073] 11) Based on the static magnetic target positioning device, the full tensor magnetic gradient data of n measurement positions of the moving magnetic target within a preset time period are obtained, where n is a natural number greater than or equal to 3.

[0074] Specifically, the magnetic target positioning device of the present invention is in a stationary state during measurement, and the magnetic target is in a moving state. The full tensor magnetic gradient data of the magnetic target is obtained by the magnetic target positioning device within a preset time period, and the full tensor magnetic gradient data at different time points correspond to different measurement positions on the motion trajectory, and the obtained data corresponds to at least three different measurement positions; in theory, the more measurement positions there are, the more accurate the positioning is, but the amount of data that needs to be processed is relatively larger, so the number of measurement positions can be set according to actual needs.

[0075] More specifically, when the number of corresponding measurement positions m (greater than or equal to n) is relatively large, a portion of the data can be selected as needed to obtain data with a high signal-to-noise ratio (for subsequent signal recognition and processing, as an example, the signal-to-noise ratio is not less than 2; including but not limited to 3, 5, 6, 10), thereby improving positioning precision and accuracy. As an example, data corresponding to m measurement positions are obtained, where m is greater than 5, including but not limited to 7, 10, 15, 18, and 20, which are not described one by one here; the characteristic quantity (also called invariant) of the full tensor magnetic gradient matrix is ​​used as the basis for selecting data, the threshold of the characteristic quantity of the full tensor magnetic gradient matrix is ​​set, and the full tensor magnetic gradient data with the characteristic quantity greater than the threshold is retained, thereby obtaining data with a signal-to-noise ratio that meets the processing requirements. In this example, the characteristic quantity of the full tensor magnetic gradient matrix is ​​embodied in the form of a Frobenius norm.

[0076] 12) Select one of the measurement positions as the initial position of the magnetic target, obtain the measurement positions of the magnetic target based on the initial position and the full tensor invariant in the full tensor magnetic gradient data, and fit the motion trajectory characteristics of the magnetic target to obtain the minimum mean square error after fitting.

[0077] Specifically, in this embodiment, the initial position selected for the first time is random and is assigned an initial value (therefore, the distance from the initial position selected for the first time to the magnetic target positioning device is known); in actual use, the middle position, the two end positions, etc. can also be selected as the initial position as needed, which will not be elaborated here.

[0078] Specifically, the method for obtaining each measured position of the magnetic target based on the initial position of the magnetic target and the full tensor invariant includes:

[0079] 21) Calculate the ratio of the distance from the initial position to the magnetic target positioning device to the distance from each other measured position to be calculated to the magnetic target positioning device, and then obtain the distance from each measured position of the magnetic target to the magnetic target positioning device; it should be noted that this distance only has a size but no direction. As an example, the following relationship is satisfied:

[0080]

[0081] in, is the ratio of the distance from the initial position to the magnetic target positioning device to the distance from the i-th measured position to be calculated to the magnetic target positioning device, i is a natural number less than or equal to n-1; R0 is the distance from the initial position to the magnetic target positioning device; R i is the distance from the i-th measurement position to the magnetic target positioning device; NT0 is the full tensor invariant of the initial position, NT i is the full tensor invariant of the i-th measurement position, satisfying: λ1, λ2, and λ3 are the eigenvalues ​​of the full tensor magnetic gradient matrix, respectively, and λ2≥λ3≥λ1, |λ1|≥|λ3|, |λ2|≥|λ3|, μ0 is the vacuum magnetic permeability, M is the modulus of the magnetic moment, and R is the distance between the magnetic source (measurement position) and the magnetic target positioning device.

[0082] 22) Calculate and determine the position vector of the magnetic target; specifically including:

[0083] First, 221) the unit vector of the position vector of the magnetic target is obtained based on the full tensor magnetic gradient data. The unit vector of the position vector of the magnetic target is satisfy:

[0084]

[0085] Among them, a1 and a2 are coefficients represented by eigenvalues, This step calculates four unit vectors, and there is an imaginary solution.

[0086] Further, 222) removes two virtual solutions of the position vector of the magnetic target according to the undetermined positive and negative magnetic moment direction vector. According to the full tensor magnetic gradient characteristics: the eigenvector corresponding to the eigenvalue with the smallest absolute value of the full tensor magnetic gradient matrix is ​​perpendicular to the magnetic moment vector and the position vector, that is, V3·m=0(6), V3·r=0(7) It can be seen that the eigenvectors V3 of the two measurement positions are respectively the normal vectors of the plane formed by the magnetic moment vector and the position vector. If the magnetic moment is fixed, that is, the direction vector of the magnetic moment vector does not change, then according to the knowledge of spatial geometry, the vector product of the eigenvectors V3 of the two measurement positions is the direction vector of the magnetic moment. The unit vector of the magnetic moment vector of the magnetic target is satisfy:

[0087]

[0088] Where V3 is the eigenvector of the eigenvalue λ3 (the eigenvalue with the smallest absolute value), m is the magnetic moment vector, r is the position vector; β1 and β2 are the coefficients represented by the eigenvalue,

[0089] like Figure 2 As shown, based on the obtained undetermined positive and negative magnetic moment direction vector combined with the following relations (11) to (14) (since the angle between the magnetic moment vector and the position vector is determined, there are only four combinations of unit vectors of the magnetic moment vector and the position vector that can satisfy it) two virtual solutions of the magnetic moment vector and the position vector can be directly removed:

[0090]

[0091] Among them, V1 is the eigenvector of the eigenvalue λ1 of the full tensor magnetic gradient matrix, and V2 is the eigenvector of the eigenvalue λ2 of the full tensor magnetic gradient matrix.

[0092] Finally, 223) is supplemented by the actual priori condition, and then a virtual solution is removed to determine the unique solution of the unit vector of the position vector of the magnetic target. The priori condition includes but is not limited to the approximate direction of the magnetic target. Any priori condition that can determine the unique solution of the unit vector of the position vector of the magnetic target is applicable to the present invention, and is not limited to this embodiment.

[0093] It should be noted that any method of determining the unit vector of the position vector of the magnetic target is applicable to the present invention and will not be described in detail here.

[0094] 23) According to the distance between the magnetic target positioning device and the corresponding measurement position, and the unit vector of the position vector of the magnetic target, the position of the magnetic target is obtained; when the distance and direction are determined, accurate position information can be obtained, such as Figure 3 shown.

[0095] Specifically, the method of fitting and obtaining the minimum mean square error includes:

[0096] 31) Analyze the motion trajectory of the magnetic target according to the prior conditions and express it abstractly with mathematical formulas. The prior conditions include but are not limited to the type of magnetic target. In the real world, the motion trajectory of the magnetic target is usually regular, and its motion trajectory can be simply judged based on the type of the magnetic target; for example, the short-term motion trajectory of a ship sailing on the water can be described as a straight line in space, or even simplified as a straight line in a plane.

[0097] More specifically, when the motion trajectory of the magnetic target is a straight line in space, the mathematical formula satisfies:

[0098]

[0099] Among them, x, y, z are the coordinates of the measured position of the magnetic target, x0, y0, z0 are the coordinates of the initial position of the magnetic target, and P, Q, H are the direction vectors of the spatial straight line abstracted from the motion trajectory.

[0100] When the motion trajectory of the magnetic target is a straight line in the plane, the mathematical formula satisfies:

[0101]

[0102] Among them, x, y, z are the coordinates of the measured position of the magnetic target, and a, b, c are the parameters of the plane straight line abstracted from the motion trajectory.

[0103] When the motion trajectory of the magnetic target is other situations, corresponding mathematical formulas can be established according to actual conditions, which will not be described in detail here.

[0104] 32) Based on the least squares or intelligent algorithm, the motion trajectory of the calculated magnetic target is fitted using an abstract mathematical formula to minimize the mean square error. In this example, the mean square error satisfies:

[0105]

[0106] Among them, H0 is the mean square error, f xi 、f yi 、f zi is the magnetic target position solved according to the set initial magnetic target position (x0, y0, z0), k xi , k yi , k zi is the spatial position after fitting according to the mathematical formula.

[0107] 33) According to the fitting results, the minimum mean square error after fitting is obtained.

[0108] It should be noted that any algorithm and method that can calculate the minimum mean square error is applicable to the present invention, and is not limited to this embodiment.

[0109] 13) Changing the initial position of the magnetic target and executing step 12) repeatedly until the minimum mean square error corresponding to all initial positions is calculated.

[0110] Specifically, as an example, an intelligent algorithm is used to change the initial position of the magnetic target (one of the measurement positions), and the intelligent algorithm includes but is not limited to the gray wolf algorithm. When the algorithm ends, the setting of the initial position ends, that is, the initial position may be part of each measurement position, or it may be all, which is determined based on the actual algorithm. As another example, the initial position of the magnetic target (one of the measurement positions) is changed by regional traversal. At this time, each measurement position is used as the initial position to calculate the minimum mean square error.

[0111] 14) The initial position with the best minimum mean square error after fitting is taken as the final solution. The position information of the magnetic target is obtained based on the final solution of the full tensor invariant and the initial position to achieve the positioning of the magnetic target.

[0112] Specifically, the initial position with the smallest minimum mean square error is selected as the final initial position, and the position information of the magnetic target is obtained based on the final solution; as an example, the position information of the magnetic target corresponding to the final solution is obtained directly from step 12) or step 13) (see step 21) to step 23)); as another example, the position information of the magnetic target is recalculated based on the final solution and the full tensor invariant. At this time, each measured position may be partially or completely different from the measured positions in step 12) and step 13).

[0113] At present, the method of positioning based on full tensor invariant can be realized by a single full tensor magnetic gradient measurement component or a combination of multiple three-axis magnetometers, while the present invention adopts a single full tensor magnetic gradient measurement component, obtains a section of full tensor magnetic gradient information in a static state, and then realizes magnetic target positioning through full tensor magnetic gradient data of the point position of a single magnetic target positioning device, and based on full tensor invariant and motion trajectory constraints. The currently disclosed method of realizing magnetic target positioning in a static state requires the total field information of the magnetic target or the initial position of the magnetic target, while the present invention can realize the real magnetic target positioning in a static state.

[0114] like Figure 4 As shown, the present invention also provides a magnetic target positioning device, including: a full tensor magnetic gradient measurement component 1, a bracket 2 and a measurement and control component 3.

[0115] like Figure 4 As shown, the bracket 2 is used to carry the full tensor magnetic gradient measurement component 1 and the measurement and control component 3.

[0116] Specifically, in this example, the bracket 2 is disposed on the ground 6. In actual use, the bracket 2 can be disposed on any device that maintains a fixed position relative to the ground, and is not limited to the illustrations of the present invention.

[0117] like Figure 4 As shown, the full tensor magnetic gradient measurement assembly 1 is used to detect a magnetic target 5 (magnetic source).

[0118] Specifically, the structure of the full tensor magnetic gradient measurement component 1 is not limited, and any structure that can measure the gradients of the three components of the magnetic field vector in three directions in space is applicable.

[0119] like Figure 4 As shown, the measurement and control component 3 is electrically connected to the full tensor magnetic gradient measurement component 1, and is used to provide a test signal to the full tensor magnetic gradient measurement component 1, and read and process the data collected by the full tensor magnetic gradient measurement component 1.

[0120] As another example of the present invention, when the position of the magnetic target positioning device is unknown, the magnetic target positioning device further includes a locator 4, which is arranged on the bracket 2 and is used to obtain the longitude and latitude and / or altitude information of the full tensor magnetic gradient measurement assembly 1. If the position of the magnetic target positioning device can be obtained from the relative position relationship between other objects at known positions and the magnetic target positioning device, the locator 4 does not need to be set.

[0121] Specifically, the locator 4 includes but is not limited to a GPS receiver, which is used to obtain the longitude, latitude and altitude information of the magnetic target positioning device, and correct the longitude, latitude and altitude information of the full tensor magnetic gradient measurement component 1 (i.e., the position information of the magnetic target positioning device in the above method) according to the spatial position deviation of the locator 4 and the probe of the full tensor magnetic gradient measurement component 1, and then correct the longitude, latitude and altitude information of the magnetic target in the geographic coordinates, wherein the spatial position deviation of the locator 4 and the full tensor magnetic gradient measurement component 1 can be completed by common measuring tools such as a ruler, which will not be elaborated here.

[0122] In summary, the present invention provides a static positioning method and positioning device for a magnetic target, including: obtaining full tensor magnetic gradient data of n measurement positions of a moving magnetic target within a preset time period based on a static magnetic target positioning device, where n is a natural number greater than or equal to 3; selecting one of the measurement positions as the initial position of the magnetic target, obtaining each measurement position of the magnetic target based on the initial position and the full tensor invariant in the full tensor magnetic gradient data, and fitting according to the motion trajectory characteristics of the magnetic target to obtain the minimum mean square error after fitting; changing the initial position of the magnetic target and cyclically executing the previous step until the minimum mean square error corresponding to all initial positions is calculated; taking the initial position with the optimal minimum mean square error after fitting as the final solution, obtaining the position information of the magnetic target based on the full tensor invariant and the final solution of the initial position, and realizing the positioning of the magnetic target. The method of the present invention realizes magnetic target positioning based on the full tensor invariant and motion trajectory constraints, and the device constructed by the method can simply realize the positioning of a fixed magnetic moment magnetic source through a set of measurement processes and test data post-processing; the present invention can realize magnetic source positioning in a static state, with high positioning accuracy and low cost. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

[0123] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A static positioning method for a magnetic target, characterized in that: The magnetic target positioning method at least comprises: 11) obtaining full tensor magnetic gradient data of n measurement positions of a moving magnetic target within a preset time period based on a static magnetic target positioning device, where n is a natural number greater than or equal to 3; 12) selecting one of the measurement positions as the initial position of the magnetic target, obtaining the measurement positions of the magnetic target based on the initial position and the full tensor invariant in the full tensor magnetic gradient data, and fitting according to the motion trajectory characteristics of the magnetic target to obtain the minimum mean square error after fitting; 13) changing the initial position of the magnetic target and executing step 12) repeatedly until the minimum mean square error corresponding to all initial positions is calculated; 14) The initial position with the best minimum mean square error after fitting is taken as the final solution, and the position information of the magnetic target is obtained based on the full tensor invariant and the final solution of the initial position to achieve the positioning of the magnetic target.

2. The static positioning method of a magnetic target according to claim 1, characterized in that: In step 11), full tensor gradient data of m measurement positions are obtained, and a threshold of a full tensor magnetic gradient matrix characteristic quantity is set, and full tensor magnetic gradient data whose characteristic quantity is greater than the threshold is retained to obtain data whose signal-to-noise ratio meets the processing requirements; wherein m is a natural number greater than or equal to n.

3. The static positioning method of a magnetic target according to claim 1, characterized in that: The initial position of the magnetic target is changed by using the grey wolf algorithm or the area traversal method.

4. The static positioning method of a magnetic target according to claim 1, characterized in that: The method for obtaining each measurement position of the magnetic target based on the initial position of the magnetic target and the full tensor invariant includes: 21) respectively calculating the ratio of the distance from the initial position to the magnetic target positioning device to the distance from each other measurement position to be calculated to the magnetic target positioning device, thereby obtaining the distance from each measurement position of the magnetic target to the magnetic target positioning device; 22) a unit vector of the magnetic moment vector, determining the position vector of the magnetic target; 23) The position of the magnetic target is obtained based on the distance between the magnetic target positioning device and the corresponding measurement position, and the unit vector of the position vector of the magnetic target.

5. The static positioning method of a magnetic target according to claim 4, characterized in that: In step 21), the ratio satisfies: in, is the ratio of the distance from the initial position to the magnetic target positioning device to the distance from the i-th measured position to be calculated to the magnetic target positioning device, i is a natural number less than or equal to n-1; R0 is the distance from the initial position to the magnetic target positioning device, R i is the distance from the i-th measurement position to the magnetic target positioning device, NT0 is the full tensor invariant of the initial position, NT i is the full tensor invariant at the i-th measurement position.

6. The static positioning method of a magnetic target according to claim 4, characterized in that: Step 22) includes: 221) obtaining four unit vectors of the position vector of the magnetic target based on the full tensor magnetic gradient data; 222) removing two imaginary solutions of the position vector of the magnetic target according to the magnetic moment direction vector whose positive and negative are not determined; 223) is used with the aid of actual a priori conditions to determine a unique solution for the unit vector of the position vector of the magnetic target.

7. The static positioning method of a magnetic target according to claim 6, characterized in that: In step 221), four unit vectors of the position vector of the magnetic target are calculated based on the following formula: in, is the unit vector of the position vector of the magnetic target, λ1, λ2, λ3 are the eigenvalues ​​of the full tensor magnetic gradient matrix, and λ2≥λ3≥λ1, |λ1|≥|λ3|, |λ2|≥|λ3|.

8. The static positioning method of a magnetic target according to claim 6, characterized in that: In step 222), the virtual solution is removed based on the following formula: V3·m=0; in, is the unit vector of the magnetic moment vector of the magnetic target, λ1 and λ2 are the eigenvalues ​​of the full tensor magnetic gradient matrix, and λ2≥λ3≥λ1, |λ1|≥|λ3|, |λ2|≥|λ3|; V1 is the eigenvector of the eigenvalue λ1 of the full tensor magnetic gradient matrix, V2 is the eigenvector of the eigenvalue λ2 of the full tensor magnetic gradient matrix, and V3 is the eigenvector corresponding to the eigenvalue λ3 of the full tensor magnetic gradient matrix.

9. The static positioning method of a magnetic target according to claim 6, characterized in that: The prior conditions in step 223) include: the approximate direction of the magnetic target.

10. The static positioning method of a magnetic target according to claim 1, characterized in that: The method for fitting and obtaining the minimum mean square error in step 12) includes: 31) analyzing the motion trajectory of the magnetic target according to a priori conditions and expressing it abstractly using mathematical formulas; 32) Based on the least squares or intelligent algorithm, the motion trajectory of the magnetic target is fitted using the mathematical formula to minimize the mean square error; 33) According to the fitting results, the minimum mean square error after fitting is obtained.

11. The static positioning method of a magnetic target according to claim 10, characterized in that: The prior conditions in step 31) include the type of the magnetic target.

12. The static positioning method of a magnetic target according to claim 10, characterized in that: When the motion trajectory of the magnetic target is a straight line in space, the mathematical formula satisfies: Among them, x, y, z are the positions of the magnetic target, x0, y0, z0 are the initial positions of the magnetic target, and P, Q, H are the direction vectors of the spatial straight line abstracted from the motion trajectory.

13. The static positioning method of a magnetic target according to claim 10, characterized in that: When the motion trajectory of the magnetic target is a straight line in a plane, the mathematical formula satisfies: Wherein, x, y, z are the positions of the magnetic target, and a, b, c are the parameters of the plane straight line abstracted from the motion trajectory.

14. The static positioning method of a magnetic target according to claim 1 or 10, characterized in that: The mean square error satisfies: Among them, H0 is the mean square error, f xi 、fyi、f zi is the magnetic target position solved according to the set initial magnetic target position (x0, y0, z0), k xi , k yi , k zi is the spatial position after fitting according to the mathematical formula.

15. A magnetic target positioning device, characterized in that: The magnetic target positioning device at least comprises: a bracket, a full tensor magnetic gradient measurement component and a measurement and control component; The bracket is used to carry the full tensor magnetic gradient measurement component and the measurement and control component; The full tensor magnetic gradient measurement component is used to detect magnetic targets; The measurement and control component is electrically connected to the full tensor magnetic gradient measurement component, and is used to provide a test signal to the full tensor magnetic gradient measurement component and read and process the data collected by the full tensor magnetic gradient measurement component.

16. The magnetic target positioning device according to claim 15, characterized in that: The magnetic target positioning device also includes a positioner, which is arranged on the bracket and is used to obtain the longitude and latitude and / or altitude information of the full tensor magnetic gradient measurement component.

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