A three-dimensional positioning method and device based on scalar magnetic gradient and related equipment

Abstract

The application discloses a three-dimensional positioning method and device based on scalar magnetic gradient and related equipment, and the method comprises the following steps: acquiring two-dimensional scalar magnetic gradient data, the two-dimensional scalar magnetic gradient data is collected by two magnetic total field sensors which are vertically arranged in a detection area, and the record points of the two-dimensional scalar magnetic gradient data are uniformly distributed in the detection area; based on the two-dimensional scalar magnetic gradient data, two-dimensional scalar magnetic gradient energy level distribution data in a two-dimensional space formed by each group of unit orthogonal bases is acquired, the unit orthogonal bases are obtained by decomposing two-dimensional scalar magnetic gradient data generated by a magnetic dipole of a target body at an arbitrary height; based on the energy level distribution data, the horizontal positioning result and the vertical positioning result of the target body are determined. In the three-dimensional positioning process of the target body, the vector magnetic moment information of the target body is not involved, and the positioning accuracy in the vertical direction can be improved.

Description

Technical Field

[0001] This application relates to the field of magnetic exploration technology, and more specifically, to a three-dimensional positioning method, apparatus and related equipment based on scalar magnetic gradient. Background Technology

[0002] Magnetic anomaly detection (MAD) is one of the most suitable geophysical techniques for locating and mapping the distribution of ferromagnetic metallic objects. It has wide applications in fields related to national economic security and cultural development, such as resource exploration, unexploded ordnance detection, underwater vehicle detection, and archaeology. Due to the advantages of scalar magnetic sensors, such as low noise levels and insensitivity to mechanical noise from rotation and vibration, scalar magnetic anomaly detection is currently the mainstream method. Locating ferromagnetic targets based on two-dimensional planar data of scalar magnetic anomalies is also an important research direction in magnetic anomaly detection. Since the magnitude of the anomaly obtained from a single sensor is simultaneously affected by the magnetic moment parameter of the target object, and diurnal variation corrections are performed using separate geomagnetic diurnal variation stations, current research on two-dimensional magnetic anomaly location methods mainly revolves around magnetic anomaly gradient data acquired by dual-sensor or multi-sensor arrays. For two-dimensional magnetic anomaly detection, even with only one sensor, horizontal magnetic gradient information can be obtained through numerical difference of data from the same horizontal plane; therefore, the magnetic gradient obtained by multiple sensors mainly refers to the vertical direction.

[0003] In the study of locating magnetic targets using two-dimensional vertical gradient data, direct methods and iterative methods are the two main approaches. Direct methods primarily include Euler deconvolution and its derivatives. These methods can locate targets without being affected by magnetic moment parameters; however, as the sliding window moves, a large number of outliers are obtained. Iterative methods require assuming initial parameters such as the target's magnetic moment magnitude, tilt angle, deflection angle, and position. Then, nonlinear optimization theory is applied to iteratively solve for these parameters to fit the observed data. During the iteration process, the various parameters to be solved influence each other, leading to significant errors in the estimation of position parameters, especially in the vertical direction. Furthermore, iterative methods are heavily influenced by initial parameters, often resulting in non-convergence or convergence in the wrong direction. Summary of the Invention

[0004] In view of this, this application provides a three-dimensional positioning method, apparatus and related equipment based on scalar magnetic gradient, so as to achieve effective positioning of magnetic target bodies and improve the positioning accuracy in the vertical direction.

[0005] To achieve the above objectives, the first aspect of this application provides a three-dimensional localization method based on scalar magnetic gradient, comprising:

[0006] Two-dimensional scalar magnetic gradient data is acquired by two magnetic total field sensors vertically deployed in the detection area, and the recording points of the two-dimensional scalar magnetic gradient data are evenly distributed in the detection area.

[0007] Based on the two-dimensional scalar magnetic gradient data, the energy level distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of orthogonal units are obtained. The orthogonal units are obtained by decomposing the two-dimensional scalar magnetic gradient data generated by the magnetic dipole of the target body at any height.

[0008] Based on the energy level distribution data, the horizontal and vertical positioning results of the target are determined.

[0009] Preferably, the process of acquiring two-dimensional scalar magnetic gradient data includes:

[0010] Using a magnetometer, the scalar magnetic anomaly data and recording points of the two total magnetic field sensors are recorded along a preset scanning path to obtain multiple data items. Each data item includes a first scalar magnetic anomaly data, a second scalar magnetic anomaly data, and a recording point.

[0011] For each data item, the difference between the first scalar magnetic anomaly data and the second scalar magnetic anomaly data is calculated, and the difference is divided by the distance between the two magnetic total field sensors to obtain the scalar magnetic gradient data for each data item.

[0012] Based on the scalar magnetic gradient data and recording points of each data item, the scalar magnetic gradient data of each grid point is obtained using a preset interpolation method, wherein the grid is uniformly distributed in the detection area.

[0013] The two-dimensional scalar magnetic gradient data is composed of the scalar magnetic gradient data at each grid point and the coordinates of each grid point.

[0014] Preferably, the process of obtaining the energy level distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of orthogonal units based on the two-dimensional scalar magnetic gradient data includes:

[0015] Based on the two-dimensional scalar magnetic gradient data, obtain the modulus level distribution data of the two-dimensional scalar magnetic gradient on each set of identity orthogonal bases;

[0016] Based on the modulus level distribution data, the energy level distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of unit orthogonal bases is obtained.

[0017] Preferably, the unity orthogonal basis includes:

[0018]

[0019] Where (x, y) are the horizontal coordinates of the recording point, z1 and z2 are the vertical coordinates of the two magnetic field sensors, and C1(z1, z2) and C2(z1, z2) are constant coefficient expressions composed of z1 and z2, respectively.

[0020] Preferably, the process of obtaining the modulus level distribution data of the two-dimensional scalar magnetic gradient on each set of unit orthogonal bases based on the two-dimensional scalar magnetic gradient data includes:

[0021] Each set of unit orthogonal bases is extracted using a window of a preset size, resulting in multiple orthogonal base window functions;

[0022] The following equation is used to calculate the modulus level distribution data α of the two-dimensional scalar magnetic gradient on each set of unity orthogonal bases. n (x0, y0):

[0023]

[0024] Where I and J are the sizes of the window in the x and y directions, respectively, (x0, y0) are the horizontal coordinates of the center point of the window, and dΔT(x i y j ) is in (x i y j Two-dimensional scalar magnetic gradient data of grid points at ().

[0025] Preferably, the process of obtaining the energy level distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of orthogonal unit bases based on the modulus level distribution data includes:

[0026] The original horizontal distribution data E(x, y) of the energy of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of orthogonal unit bases are calculated using the following equation:

[0027]

[0028] Where, α n (x, y) represents the modulus level distribution data on the nth group of orthogonal unit basis;

[0029] The original horizontal distribution data of the energy is normalized to obtain the horizontal distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of unit orthogonal bases.

[0030] Preferably, the process of determining the horizontal and vertical positioning results of the target based on the energy level distribution data includes:

[0031] Based on the energy level distribution data, a target sub-region containing a ferromagnetic object is determined in the detection area, and the value of the energy level distribution data of the target sub-region is greater than a preset threshold.

[0032] The horizontal coordinate of the point with the largest energy level distribution data value in each target sub-region is determined as the horizontal coordinate of the target body.

[0033] The horizontal coordinate (x) of the target T y T Modulus α at point ) n (x T y T Substituting into the following equation, we obtain the vertical coordinates of the target object:

[0034]

[0035] Where dz is the distance between the two magnetic field sensors, z1 and z2 are the vertical coordinates of the two magnetic field sensors respectively, and z is the vertical distance from the target to the plane where z1 is located.

[0036] A second aspect of this application provides a three-dimensional positioning device based on a scalar magnetic gradient, comprising:

[0037] The data acquisition unit is used to acquire two-dimensional scalar magnetic gradient data, which is collected by two magnetic total field sensors vertically deployed in the detection area, and the recording points of the two-dimensional scalar magnetic gradient data are evenly distributed in the detection area.

[0038] An energy acquisition unit is used to acquire energy level distribution data of the two-dimensional scalar magnetic gradient in a two-dimensional space spanned by each set of orthogonal units, based on the two-dimensional scalar magnetic gradient data. The orthogonal units are obtained by decomposing the two-dimensional scalar magnetic gradient data generated by the magnetic dipole of the target body at any height.

[0039] The positioning calculation unit is used to determine the horizontal and vertical positioning results of the target body based on the energy level distribution data.

[0040] A third aspect of this application provides a three-dimensional positioning device based on scalar magnetic gradient, comprising: a memory and a processor;

[0041] The memory is used to store programs;

[0042] The processor is used to execute the program to implement the various steps of the above-described 3D localization method based on scalar magnetic gradient.

[0043] A fourth aspect of this application provides a storage medium having a computer program stored thereon, which, when executed by a processor, implements the various steps of the three-dimensional positioning method based on scalar magnetic gradients as described above.

[0044] As described in the above technical solution, this application first obtains two-dimensional scalar magnetic gradient data, which is collected by two magnetic field sensors vertically deployed in the detection area, and the recording points of the two-dimensional scalar magnetic gradient data are uniformly distributed in the detection area. Next, based on the two-dimensional scalar magnetic gradient data, the energy level distribution data of the two-dimensional scalar magnetic gradient in a two-dimensional space spanned by each set of orthogonal units is obtained, where the orthogonal units are obtained by decomposing the two-dimensional scalar magnetic gradient data generated by the magnetic dipole of the target body at any height. The energy level distribution data has a high signal-to-noise ratio, and regions with relatively strong energy, i.e., regions with higher values ​​of the energy level distribution data, indicate a greater likelihood of the presence of a ferromagnetic target body. Finally, based on the energy level distribution data, the horizontal and vertical positioning results of the target body can be determined. This application transforms the two-dimensional scalar magnetic gradient distribution into a two-dimensional energy distribution, improving the signal-to-noise ratio of the data. Furthermore, the three-dimensional positioning process of the target body does not involve the vector magnetic moment information of the target body and is unaffected by the magnetic moment, thus improving the positioning accuracy in the vertical direction. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0046] Figure 1 This is a schematic diagram of the three-dimensional positioning method based on scalar magnetic gradient disclosed in an embodiment of this application;

[0047] Figure 2 A two-dimensional survey line distribution diagram for magnetic anomaly detection disclosed in an embodiment of this application is illustrated;

[0048] Figure 3 The example illustrates a two-dimensional magnetic total field gradient surface obtained after using the biharmonic spline interpolation method provided in the embodiments of this application;

[0049] Figure 4 The two-dimensional orthogonal basis surface plots obtained by calculating the first and second sets of orthogonal basis functions provided in the embodiments of this application are illustrated.

[0050] Figure 5The two-dimensional orthogonal basis surface plots obtained by calculating the third and fourth sets of orthogonal basis functions provided in the embodiments of this application are illustrated.

[0051] Figure 6 The two-dimensional orthogonal basis surface plots obtained by calculating the fifth and sixth groups of orthogonal basis functions provided in the embodiments of this application are illustrated.

[0052] Figure 7 The two-dimensional orthogonal basis surface plots obtained by calculating the 7th and 8th groups of orthogonal basis functions provided in the embodiments of this application are illustrated.

[0053] Figure 8 The two-dimensional orthogonal basis surface plots obtained by calculating the 9th and 10th sets of orthogonal basis functions provided in the embodiments of this application are illustrated.

[0054] Figure 9 An example of an energy distribution curve provided in an embodiment of this application is illustrated;

[0055] Figure 10 This is a schematic diagram of a three-dimensional positioning device based on scalar magnetic gradient disclosed in an embodiment of this application;

[0056] Figure 11 This is a schematic diagram of a three-dimensional positioning device based on scalar magnetic gradient disclosed in an embodiment of this application. Detailed Implementation

[0057] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0058] The following describes a three-dimensional localization method based on scalar magnetic gradients provided in embodiments of this application. Please refer to [link to relevant documentation]. Figure 1 The three-dimensional localization method based on scalar magnetic gradient provided in this application embodiment may include the following steps:

[0059] Step S101: Obtain two-dimensional scalar magnetic gradient data.

[0060] The two-dimensional scalar magnetic gradient data was collected by two magnetic total field sensors vertically deployed in the detection area, and the recording points of the two-dimensional scalar magnetic gradient data were evenly distributed in the detection area.

[0061] Specifically, after determining the detection area, the magnetometer mounting platform (flying platform, water platform, or handheld, etc.) moves back and forth along several parallel survey lines. Two magnetic field sensors are vertically deployed in the detection area. The magnetometer simultaneously records the scalar magnetic anomaly data and coordinate information of these two magnetic field sensors in an interval sampling manner, and calculates the two-dimensional scalar magnetic gradient data by combining the distance between the two magnetic field sensors.

[0062] For example, the following can be adopted: Figure 2 The two-dimensional survey line distribution map shown is used to collect scalar magnetic anomaly data from these two magnetic total field sensors. The survey lines run due north-south, with a distance of 0.1m between adjacent measuring points and 1m between adjacent survey lines. The bottom magnetic total field sensor is 0.5m above the ground, and the top sensor is 1m above the ground. A magnetic anomaly is buried underground at the center of the detection area, with spatial coordinates (10, 10, -0.3) and a magnetic moment of 1 Am. 2 The magnetic moment inclination angle is 5° and the deflection angle is -10°. The distances between the magnetic dipole and the observation plane of the two magnetic total field sensors are 0.8m and 1.3m, respectively; the background geomagnetic field inclination angle is 30° and the deflection angle is 0°. Scalar magnetic anomaly data from the two magnetic total field sensors at each measuring point are acquired. The scalar magnetic anomaly data from these two magnetic total field sensors are then differentially processed to obtain two-dimensional scalar magnetic gradient data for each measuring point. Finally, interpolation processing is used to obtain two-dimensional scalar magnetic gradient data uniformly distributed across the detection area for each recording point. In the practical application of this application, the magnetic total field data at each measuring point is collected using equipment such as a magnetometer. In the algorithm verification stage, the magnetic total field anomaly data at each measuring point can be directly calculated using simulation calculations, and a preset Gaussian white noise (e.g., mean 0, standard deviation 5nT) is added to simulate the actual observation data.

[0063] Step S102: Based on the two-dimensional scalar magnetic gradient data, obtain the energy level distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of unit orthogonal bases.

[0064] The orthonormal basis for each group is obtained by decomposing the two-dimensional scalar magnetic gradient data generated by the magnetic dipole of the target body at arbitrary heights. The energy of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each orthonormal basis can be regarded as the square of the modulus of the two-dimensional scalar magnetic gradient on each orthonormal basis. By squaring the modulus of the two-dimensional scalar magnetic gradient, the difference between the two-dimensional scalar magnetic gradients at each recording point in the detection area is amplified, thereby improving the signal-to-noise ratio. The modulus of the two-dimensional scalar magnetic gradient on a set of orthonormal basis is defined as the projection of the two-dimensional scalar magnetic gradient onto that set of orthonormal basis.

[0065] Step S103: Based on the energy level distribution data, determine the horizontal and vertical positioning results of the target body.

[0066] This application first acquires two-dimensional scalar magnetic gradient data, which is collected by two magnetic field sensors vertically deployed in the detection area, with the recording points of the two-dimensional scalar magnetic gradient data evenly distributed in the detection area. Next, based on the two-dimensional scalar magnetic gradient data, the energy level distribution data of the two-dimensional scalar magnetic gradient in a two-dimensional space spanned by various sets of orthogonal bases is acquired, wherein the orthogonal bases are obtained by decomposing the two-dimensional scalar magnetic gradient data generated by the magnetic dipoles of the target object at arbitrary heights. The energy level distribution data has a high signal-to-noise ratio, and regions with relatively strong energy, i.e., regions with higher energy level distribution data values, indicate a greater likelihood of the presence of a ferromagnetic target object. Finally, based on the energy level distribution data, the horizontal and vertical positioning results of the target object can be determined. This application transforms the two-dimensional scalar magnetic gradient distribution into a two-dimensional energy distribution, improving the signal-to-noise ratio of the data. Furthermore, the three-dimensional positioning process of the target object does not involve the vector magnetic moment information of the target object and is unaffected by the magnetic moment, thus improving the positioning accuracy in the vertical direction.

[0067] In some embodiments of this application, the process of obtaining two-dimensional scalar magnetic gradient data in step S101 above may include:

[0068] S1. Using a magnetometer, the scalar magnetic anomaly data and recording points of the two magnetic total field sensors are recorded along a preset scanning path to obtain multiple data items.

[0069] Each data item includes a first scalar magnetic anomaly data, a second scalar magnetic anomaly data, and a recording point. It can be understood that the first and second scalar magnetic anomaly data are the scalar magnetic anomaly data detected by the two total magnetic field sensors, respectively; the recording point is the detection location when these data were detected.

[0070] S2, for each data item, calculate the difference between the first scalar magnetic anomaly data and the second scalar magnetic anomaly data, and use the difference to divide by the distance between the two magnetic total field sensors to obtain the scalar magnetic gradient data for each data item.

[0071] S3, based on the scalar magnetic gradient data and recording points of each data item, uses a preset interpolation method to obtain the scalar magnetic gradient data of each grid point.

[0072] In actual magnetic detection missions, the spacing between measuring points is usually not equal to the spacing between measuring lines, such as... Figure 2In the two-dimensional survey line distribution map shown, the spacing between measuring points is much smaller than the spacing between survey lines. Therefore, it is necessary to grid the area covered by the survey lines, and the resulting grid should be evenly distributed within the detection area to obtain grid subdivision data of the same size along two horizontal directions (i.e., horizontal and vertical). Commonly used two-dimensional gridding methods include bilinear interpolation, bicubic interpolation, spline interpolation, minimum curvature interpolation, and kriging interpolation. For the vertical distance calculation requirements involved in this application, a quadratic continuous two-dimensional interpolation method, such as biharmonic spline interpolation, is required. Figure 3 The two-dimensional scalar magnetic gradient surface plot obtained by using the biharmonic spline interpolation method is provided in the embodiments of the present invention.

[0073] Thus, the scalar magnetic gradient data and coordinates of each grid point (recording point) are obtained. The scalar magnetic gradient data and coordinates of each grid point constitute two-dimensional scalar magnetic gradient data.

[0074] In some embodiments of this application, the process of obtaining the energy level distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of unity orthogonal bases based on the two-dimensional scalar magnetic gradient data may include:

[0075] S1, based on two-dimensional scalar magnetic gradient data, obtain the modulus level distribution data of the two-dimensional scalar magnetic gradient on each set of unit orthogonal bases.

[0076] S2, based on the modulus level distribution data, obtains the energy level distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of unit orthogonal bases.

[0077] By decomposing the expression for the two-dimensional scalar magnetic gradient generated by the magnetic dipole of the target body at any observation height, a set of unity orthogonal basis function expressions corresponding to the height can be obtained. Based on this, in some embodiments of this application, assuming the magnetic dipole is located at the origin, the unity orthogonal basis mentioned in step S102 above can be expressed as the following 10 sets of unity orthogonal basis functions:

[0078]

[0079] Each unit orthogonal basis satisfies the following equation:

[0080]

[0081] Where (x, y) are the horizontal coordinates of the recording point, z1 and z2 are the vertical coordinates of the two magnetic field sensors, and C1(z1, z2) and C2(z1, z2) are constant coefficient expressions composed of z1 and z2, respectively.

[0082] For example, Figures 4-8Two-dimensional orthogonal basis surface plots calculated from the above-mentioned groups of orthogonal basis functions are provided.

[0083] In some embodiments of this application, the process of obtaining the modulus level distribution data of the two-dimensional scalar magnetic gradient on each set of identity orthogonal bases based on the two-dimensional scalar magnetic gradient data in S1 may include:

[0084] S11 uses a window of a preset size to extract each group of unit orthogonal bases, resulting in multiple orthogonal base window functions.

[0085] For example, a window of size 5 can be selected and used to truncate each group of orthonormal bases to obtain multiple orthonormal base window functions of finite length.

[0086] S12, the modulus level distribution data α of the two-dimensional scalar magnetic gradient on each set of identity orthogonal bases is calculated using the following equation. n (x0, y0):

[0087]

[0088] Where I and J are the sizes of the window in the x and y directions, respectively, (x0, y0) are the horizontal coordinates of the center point of the window, and dΔT(x i y j ) is in (x i y j Two-dimensional scalar magnetic gradient data of grid points at ().

[0089] The above formula actually calculates the inner product of the obtained orthogonal basis window function along the gridded region point by point on the two-dimensional scalar magnetic gradient data, thereby obtaining the horizontal distribution of the modulus of the two-dimensional scalar magnetic gradient in each set of unit orthogonal basis directions.

[0090] In some embodiments of this application, the process of obtaining the energy level distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of unit orthogonal bases based on the modulus level distribution data in S2 may include:

[0091] S21, the original horizontal distribution data E(x, y) of the energy of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of orthogonal unit bases are calculated using the following equation:

[0092]

[0093] Where, α n (x, y) represents the modulus level distribution data on the nth group of orthogonal unit bases.

[0094] S22, normalize the original horizontal distribution data of energy to obtain the horizontal distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of unit orthogonal bases.

[0095] This normalization process can eliminate the influence of the magnetic moment magnitude of the target object, facilitating subsequent data processing. For example, Figure 9 Energy level distribution data (i.e., energy distribution curves) are provided. As can be seen from the graph, the energy level distribution data can largely distinguish the energy differences at different grid points.

[0096] In some embodiments of this application, the process of determining the horizontal and vertical positioning results of the target based on energy level distribution data in step S103 may include:

[0097] S1, based on energy level distribution data, determines the target sub-region in the detection area where a ferromagnetic target exists.

[0098] Since the energy level distribution data has been normalized in the preceding steps, the energy values ​​within the detection area are all between 0 and 1. Based on the overall energy distribution, an appropriate threshold is selected, and areas with energy above the threshold are identified as target sub-regions containing ferromagnetic targets. For example, this threshold can be set to 0.5. Figure 9 As shown, it is easy to obtain one target sub-region.

[0099] S2, determine the horizontal coordinates of the point with the largest value of energy level distribution data in each target sub-region as the horizontal coordinates of the target body.

[0100] like Figure 9 In the energy level distribution data shown, by reading the horizontal coordinates of the energy maximum point in the target sub-region, the horizontal coordinates of the target body can be obtained as (10, 10). In practical applications, at the cost of reduced computational efficiency, the positioning accuracy can be further improved by using a denser grid.

[0101] S3, the horizontal coordinate (x) of the target body T y T Modulus α at point ) n (x T y T Substituting into the following equation, we obtain the vertical coordinates of the target object:

[0102]

[0103] Where dz represents the distance between the two magnetic field sensors, z1 and z2 are the vertical coordinates of the two magnetic field sensors respectively, and z is the vertical distance from the target to the plane containing z1. Figure 9In the example shown, the z result is 0.76m, which has a relative error of 5% compared to the actual 0.8m.

[0104] The following describes the three-dimensional positioning device based on scalar magnetic gradient provided in the embodiments of this application. The three-dimensional positioning device based on scalar magnetic gradient described below can be referred to in correspondence with the three-dimensional positioning method based on scalar magnetic gradient described above.

[0105] Please see Figure 10 The three-dimensional positioning device based on scalar magnetic gradient provided in this application embodiment may include:

[0106] The data acquisition unit 21 is used to acquire two-dimensional scalar magnetic gradient data, which is collected by two magnetic total field sensors vertically deployed in the detection area, and the recording points of the two-dimensional scalar magnetic gradient data are evenly distributed in the detection area.

[0107] The energy acquisition unit 22 is used to acquire energy level distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of orthogonal units based on the two-dimensional scalar magnetic gradient data. The orthogonal units are obtained by decomposing the two-dimensional scalar magnetic gradient data generated by the magnetic dipole of the target body at any height.

[0108] The positioning calculation unit 23 is used to determine the horizontal positioning result and the vertical positioning result of the target body based on the energy horizontal distribution data.

[0109] In some embodiments of this application, the process of the data acquisition unit 21 acquiring two-dimensional scalar magnetic gradient data may include:

[0110] Using a magnetometer, the scalar magnetic anomaly data and recording points of the two total magnetic field sensors are recorded along a preset scanning path to obtain multiple data items. Each data item includes a first scalar magnetic anomaly data, a second scalar magnetic anomaly data, and a recording point.

[0111] For each data item, the difference between the first scalar magnetic anomaly data and the second scalar magnetic anomaly data is calculated, and the difference is divided by the distance between the two magnetic total field sensors to obtain the scalar magnetic gradient data for each data item.

[0112] Based on the scalar magnetic gradient data and recording points of each data item, the scalar magnetic gradient data of each grid point is obtained using a preset interpolation method, wherein the grid is uniformly distributed in the detection area.

[0113] The two-dimensional scalar magnetic gradient data is composed of the scalar magnetic gradient data at each grid point and the coordinates of each grid point.

[0114] In some embodiments of this application, the process by which the energy acquisition unit 22 acquires energy level distribution data of the two-dimensional scalar magnetic gradient in a two-dimensional space spanned by each set of orthogonal units based on the two-dimensional scalar magnetic gradient data may include:

[0115] Based on the two-dimensional scalar magnetic gradient data, obtain the modulus level distribution data of the two-dimensional scalar magnetic gradient on each set of identity orthogonal bases;

[0116] Based on the modulus level distribution data, the energy level distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of unit orthogonal bases is obtained.

[0117] The functional expression of the orthonormal basis is consistent with the 10 sets of orthonormal basis functions described above.

[0118] In some embodiments of this application, the process by which the energy acquisition unit 22 acquires the modulus level distribution data of the two-dimensional scalar magnetic gradient on each set of identity orthogonal bases based on the two-dimensional scalar magnetic gradient data may include:

[0119] Each set of unit orthogonal bases is extracted using a window of a preset size, resulting in multiple orthogonal base window functions;

[0120] The following equation is used to calculate the modulus level distribution data α of the two-dimensional scalar magnetic gradient on each set of unity orthogonal bases. n (x0, y0):

[0121]

[0122] Where I and J are the sizes of the window in the x and y directions, respectively, (x0, y0) are the horizontal coordinates of the center point of the window, and dΔT(x i y j ) is in (x i y j Two-dimensional scalar magnetic gradient data of grid points at ().

[0123] In some embodiments of this application, the process by which the energy acquisition unit 22 acquires the energy level distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of orthogonal unit bases based on the modulus level distribution data may include:

[0124] The original horizontal distribution data E(x, y) of the energy of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of orthogonal unit bases are calculated using the following equation:

[0125]

[0126] Where, α n(x, y) represents the modulus level distribution data on the nth group of orthogonal unit basis;

[0127] The original horizontal distribution data of the energy is normalized to obtain the horizontal distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of unit orthogonal bases.

[0128] In some embodiments of this application, the process by which the positioning calculation unit 23 determines the horizontal and vertical positioning results of the target object based on the energy level distribution data may include:

[0129] Based on the energy level distribution data, a target sub-region containing a ferromagnetic object is determined in the detection area, and the value of the energy level distribution data of the target sub-region is greater than a preset threshold.

[0130] The horizontal coordinate of the point with the largest energy level distribution data value in each target sub-region is determined as the horizontal coordinate of the target body.

[0131] The horizontal coordinate (x) of the target T y T Modulus α at point ) n (x T y T Substituting into the following equation, we obtain the vertical coordinates of the target object:

[0132]

[0133] Where dz is the distance between the two magnetic field sensors, z1 and z2 are the vertical coordinates of the two magnetic field sensors respectively, and z is the vertical distance from the target to the plane where z1 is located.

[0134] The 3D positioning device based on scalar magnetic gradient provided in this application can be applied to 3D positioning equipment based on scalar magnetic gradient, such as computers. Optionally, Figure 11 The hardware structure block diagram of a 3D positioning device based on scalar magnetic gradient is shown. (Refer to...) Figure 11 The hardware structure of a 3D positioning device based on scalar magnetic gradient may include: at least one processor 31, at least one communication interface 32, at least one memory 33 and at least one communication bus 34.

[0135] In this embodiment, the number of processor 31, communication interface 32, memory 33 and communication bus 34 is at least one, and processor 31, communication interface 32 and memory 33 communicate with each other through communication bus 34;

[0136] The processor 31 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0137] The memory 33 may include high-speed RAM, and may also include non-volatile memory, such as at least one disk storage device;

[0138] The memory 33 stores a program, and the processor 31 can call the program stored in the memory 33. The program is used for:

[0139] Two-dimensional scalar magnetic gradient data is acquired by two magnetic total field sensors vertically deployed in the detection area, and the recording points of the two-dimensional scalar magnetic gradient data are evenly distributed in the detection area.

[0140] Based on the two-dimensional scalar magnetic gradient data, the energy level distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of orthogonal units are obtained. The orthogonal units are obtained by decomposing the two-dimensional scalar magnetic gradient data generated by the magnetic dipole of the target body at any height.

[0141] Based on the energy level distribution data, the horizontal and vertical positioning results of the target are determined.

[0142] Optionally, the refined and extended functions of the program can be found in the description above.

[0143] This application embodiment also provides a storage medium that can store a program suitable for execution by a processor, the program being used for:

[0144] Two-dimensional scalar magnetic gradient data is acquired by two magnetic total field sensors vertically deployed in the detection area, and the recording points of the two-dimensional scalar magnetic gradient data are evenly distributed in the detection area.

[0145] Based on the two-dimensional scalar magnetic gradient data, the energy level distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of orthogonal units are obtained. The orthogonal units are obtained by decomposing the two-dimensional scalar magnetic gradient data generated by the magnetic dipole of the target body at any height.

[0146] Based on the energy level distribution data, the horizontal and vertical positioning results of the target are determined.

[0147] Optionally, the refined and extended functions of the program can be found in the description above.

[0148] In summary:

[0149] This application first acquires two-dimensional scalar magnetic gradient data, which is collected by two magnetic field sensors vertically deployed in the detection area, with the recording points of the two-dimensional scalar magnetic gradient data evenly distributed in the detection area. Next, based on the two-dimensional scalar magnetic gradient data, the energy level distribution data of the two-dimensional scalar magnetic gradient in a two-dimensional space spanned by various sets of orthogonal bases is acquired, wherein the orthogonal bases are obtained by decomposing the two-dimensional scalar magnetic gradient data generated by the magnetic dipoles of the target object at arbitrary heights. The energy level distribution data has a high signal-to-noise ratio, and regions with relatively strong energy, i.e., regions with higher energy level distribution data values, indicate a greater likelihood of the presence of a ferromagnetic target object. Finally, based on the energy level distribution data, the horizontal and vertical positioning results of the target object can be determined. This application transforms the two-dimensional scalar magnetic gradient distribution into a two-dimensional energy distribution, improving the signal-to-noise ratio of the data. Furthermore, the three-dimensional positioning process of the target object does not involve the vector magnetic moment information of the target object and is unaffected by the magnetic moment, thus improving the positioning accuracy in the vertical direction.

[0150] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0151] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can be referred to each other.

[0152] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A three-dimensional positioning method based on scalar magnetic gradient, characterized in that, include: Two-dimensional scalar magnetic gradient data is acquired by two magnetic total field sensors vertically deployed in the detection area, and the recording points of the two-dimensional scalar magnetic gradient data are evenly distributed in the detection area. Based on the two-dimensional scalar magnetic gradient data, the energy level distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of orthogonal units are obtained. The orthogonal units are obtained by decomposing the two-dimensional scalar magnetic gradient data generated by the magnetic dipole of the target body at any height. Based on the energy level distribution data, the horizontal and vertical positioning results of the target body are determined. The process of obtaining the energy level distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of unit orthogonal bases based on the aforementioned two-dimensional scalar magnetic gradient data includes: Based on the two-dimensional scalar magnetic gradient data, obtain the modulus level distribution data of the two-dimensional scalar magnetic gradient on each set of identity orthogonal bases; Based on the modulus level distribution data, the energy level distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of unit orthogonal bases is obtained; The orthonormal basis includes: ； in, The horizontal coordinates of the recorded point are: , The vertical coordinates of the two magnetic field sensors are respectively... , They are respectively from and Form a constant coefficient expression.

2. The method according to claim 1, characterized in that, The process of acquiring two-dimensional scalar magnetic gradient data includes: Using a magnetometer, the scalar magnetic anomaly data and recording points of the two total magnetic field sensors are recorded along a preset scanning path to obtain multiple data items. Each data item includes a first scalar magnetic anomaly data, a second scalar magnetic anomaly data, and a recording point. For each data item, the difference between the first scalar magnetic anomaly data and the second scalar magnetic anomaly data is calculated, and the difference is divided by the distance between the two magnetic total field sensors to obtain the scalar magnetic gradient data for each data item. Based on the scalar magnetic gradient data and recording points of each data item, the scalar magnetic gradient data of each grid point is obtained using a preset interpolation method, wherein the grid is uniformly distributed in the detection area. The two-dimensional scalar magnetic gradient data is composed of the scalar magnetic gradient data at each grid point and the coordinates of each grid point.

3. The method according to claim 1, characterized in that, The process of obtaining the modulus level distribution data of the two-dimensional scalar magnetic gradient on each set of unit orthogonal bases based on the aforementioned two-dimensional scalar magnetic gradient data includes: Each set of unit orthogonal bases is extracted using a window of a preset size, resulting in multiple orthogonal base window functions; The modulus level distribution data of the two-dimensional scalar magnetic gradient on each set of unity orthogonal bases are calculated using the following equations. : ； Where I and J represent the size of the window in the x and y directions, respectively. The horizontal coordinates of the center point of the window are: In order to be in Two-dimensional scalar magnetic gradient data at grid points.

4. The method according to claim 1, characterized in that, The process of obtaining the energy level distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of unit orthogonal bases based on the aforementioned modulus level distribution data includes: The raw horizontal distribution data of the energy of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of orthogonal unit bases are obtained by calculating using the following equations. : ； in, The modulus level distribution data on the nth group of orthonormal basis; The original horizontal distribution data of the energy is normalized to obtain the horizontal distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of unit orthogonal bases.

5. The method according to claim 4, characterized in that, The process of determining the horizontal and vertical positioning results of the target object based on the energy level distribution data includes: Based on the energy level distribution data, a target sub-region containing a ferromagnetic object is determined in the detection area, and the value of the energy level distribution data of the target sub-region is greater than a preset threshold. The horizontal coordinate of the point with the largest energy level distribution data value in each target sub-region is determined as the horizontal coordinate of the target body. The horizontal coordinates of the target Modulus at Substituting into the following equation, we obtain the vertical coordinates of the target object: ； in, The distance between the two magnetic field sensors. , The vertical coordinates of the two magnetic field sensors are respectively... For the target body to The vertical distance to the plane in which it is located.

6. A three-dimensional positioning device based on scalar magnetic gradient, characterized in that, include: The data acquisition unit is used to acquire two-dimensional scalar magnetic gradient data, which is collected by two magnetic total field sensors vertically deployed in the detection area, and the recording points of the two-dimensional scalar magnetic gradient data are evenly distributed in the detection area. An energy acquisition unit is used to acquire energy level distribution data of the two-dimensional scalar magnetic gradient in a two-dimensional space spanned by each set of orthogonal units, based on the two-dimensional scalar magnetic gradient data. The orthogonal units are obtained by decomposing the two-dimensional scalar magnetic gradient data generated by the magnetic dipole of the target body at any height. The positioning calculation unit is used to determine the horizontal and vertical positioning results of the target body based on the energy horizontal distribution data. The process of obtaining the energy level distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of unit orthogonal bases based on the aforementioned two-dimensional scalar magnetic gradient data includes: Based on the two-dimensional scalar magnetic gradient data, obtain the modulus level distribution data of the two-dimensional scalar magnetic gradient on each set of identity orthogonal bases; Based on the modulus level distribution data, the energy level distribution data of the two-dimensional scalar magnetic gradient in the two-dimensional space spanned by each set of unit orthogonal bases is obtained; The orthonormal basis includes: ； in, The horizontal coordinates of the recorded point are: , The vertical coordinates of the two magnetic field sensors are respectively... , They are respectively from and Form a constant coefficient expression.

7. A three-dimensional positioning device based on scalar magnetic gradient, characterized in that, include: Memory and processor; The memory is used to store programs; The processor is used to execute the program to implement each step of the three-dimensional positioning method based on scalar magnetic gradient as described in any one of claims 1 to 5.

8. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements each step of the three-dimensional positioning method based on scalar magnetic gradient as described in any one of claims 1 to 5.

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