Overhead transmission line positioning method and system

Abstract

The invention relates to the technical field of power line inspection, in particular to an overhead transmission line positioning method and system. The method comprises the following steps: acquiring at least one group of three-axis magnetic field measurement data in a space adjacent to a to-be-measured overhead transmission line; for any group of three-axis magnetic field measurement data, constructing a magnetic gradient tensor matrix corresponding to the central points of the four measurement point positions; obtaining the ratio of the magnetic field amplitude of the central point corresponding to the four measurement point positions to the spectral norm of the corresponding magnetic gradient tensor matrix, and obtaining the distance between the overhead transmission line to be measured and the central point corresponding to the four measurement point positions as the distance data of the overhead transmission line to be measured; and obtaining three feature vectors corresponding to the magnetic gradient tensor matrix, and obtaining a space direction vector of the overhead transmission line to be detected as trend data of the overhead transmission line to be detected. According to the invention, high-precision non-contact positioning of the distance and direction of the power transmission line is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power line inspection, in particular to an overhead power transmission line positioning method and system. BACKGROUND

[0002] In recent years, the unmanned aerial vehicle (UAV) technology has been widely applied in the power system inspection field due to its advantages such as flexibility, low cost, and adaptability to complex terrain. In the intelligent inspection task of the UAV autonomously flying along the power transmission line (i.e., "flying along the line"), how to accurately perceive the relative position (distance and direction) of the power transmission line in real time is a key technical bottleneck for realizing the autonomous navigation and obstacle avoidance of the UAV. The UAV can efficiently complete the intelligent inspection of the flight path of the power transmission tower, insulator, and hardware fittings, and acquire the position and direction of the overhead power transmission line by carrying visible light, infrared, laser radar, and other sensors. At present, the methods based on machine vision or radar sensing path generally have disadvantages such as being unable to penetrate the obstruction and being sensitive to light.

[0003] Although the power transmission line recognition based on the magnetic field distribution characteristics can utilize the spatial magnetic field distribution characteristics of the power transmission line to calculate the relative position of the overhead power transmission line and a point in the surrounding space, and then recognize the position of the overhead power transmission line based on the coordinate position of the point, and can overcome the disadvantages of other near-field sensing methods, it has advantages such as being able to penetrate the obstruction, being available at day and night, and being insensitive to light; however, there is no related research on how to accurately acquire the magnetic field data of the local space around the overhead power transmission line.

[0004] The commonly used magnetic field sensing sensing path currently usually relies on a single point or a small number of point magnetometers to realize, and has the following defects:

[0005] 1) Weak ability to offset the geomagnetic background and environmental uniform magnetic field, and inconsistent zero offset and scale result in time drift of the result;

[0006] 2) It is difficult to reliably restore the spatial geometric relationship of the conductor by only relying on a single point vector or scalar magnetic field, and it is sensitive to current amplitude changes, and it is difficult to give a stable pointing direction and distance from the conductor;

[0007] 3) In the working conditions of multiple parallel conductors, corners, intersections, etc., the magnetic field superposition causes ambiguity in solving, and there is a lack of effective target separation mechanism;

[0008] 4) The attitude changes, asynchronous sampling, local electromagnetic interference, and sensor installation angle difference commonly seen in engineering further reduce the repeatability and consistency of geometric solving. SUMMARY

[0009] The application provides an overhead power transmission line positioning method and system, which can solve the technical problem of real-time and stable sensing of the magnetic field around the power transmission line during the flight of the unmanned aerial vehicle, and realize high-precision measurement and dynamic collection of the local three-dimensional magnetic field around the overhead power transmission line.

[0010] In an overhead power transmission line positioning method of the present disclosure, comprising,

[0011] At least one set of three-axis magnetic field measurement data at the space adjacent to the overhead power transmission line to be measured is obtained; wherein one set of three-axis magnetic field measurement data includes three-axis magnetic field measurement data of four measurement points, and the four measurement points are arranged in a square array at the same plane;

[0012] For any one set of three-axis magnetic field measurement data, a magnetic gradient tensor matrix of the center point of the corresponding four measurement points is constructed;

[0013] The ratio of the magnetic field amplitude of the center point of the corresponding four measurement points to the spectral norm of the corresponding magnetic gradient tensor matrix is obtained, and the distance between the overhead power transmission line to be measured and the center point of the corresponding four measurement points is obtained as the distance data of the overhead power transmission line to be measured;

[0014] Three eigenvectors of the corresponding magnetic gradient tensor matrix are obtained, the spatial direction vector of the overhead power transmission line to be measured is obtained, and the strike data of the overhead power transmission line to be measured is obtained.

[0015] As a preferred, when the number of the at least one set of three-axis magnetic field measurement data is not less than 1, the distance data and the strike data of the overhead power transmission line to be measured are obtained based on the distance between the overhead power transmission line to be measured and the center point of the corresponding four measurement points and the spatial direction vector of the overhead power transmission line to be measured corresponding to each set of three-axis magnetic field measurement data.

[0016] As a preferred, for any one set of three-axis magnetic field measurement data, the magnetic gradient tensor matrix of the center point of the corresponding four measurement points is,

[0017] ;

[0018] Wherein d is the diagonal distance of the four measurement points, 、 and is the magnetic field measurement data of one of the four measurement points on the x-axis, y-axis and z-axis, 、 and is the magnetic field measurement data of the other of the four measurement points on the x-axis, y-axis and z-axis, 、 and is the magnetic field measurement data of the third of the four measurement points on the x-axis, y-axis and z-axis, 、 and are the magnetic field measurement data on x-axis, y-axis and z-axis of the fourth one of the four measurement points;

[0019] wherein the one and the third of the four measurement points are diagonally distributed, and the second and the fourth of the four measurement points are diagonally distributed.

[0020] As preferred, for any set of three-axis magnetic field measurement data, the magnetic field amplitude of the center point corresponding to the four measurement points is obtained by measurement or based on the mean value of the three-axis magnetic field measurement data of the corresponding four measurement points.

[0021] As preferred, for any set of three-axis magnetic field measurement data, the spectral norm obtaining step of the corresponding magnetic gradient tensor matrix comprises,

[0022] obtaining three eigenvalues of the corresponding magnetic gradient tensor matrix 、 and ; wherein, and are opposite numbers, is 0;

[0023] The spectral norm of the corresponding magnetic gradient tensor matrix is the absolute value of the maximum eigenvalue.

[0024] As preferred, for any set of three-axis magnetic field measurement data, based on the three eigenvalues 、 and of the corresponding magnetic gradient tensor matrix, three eigenvectors 、 and of the corresponding magnetic gradient tensor matrix are obtained, specifically,

[0025] substitute the three eigenvalues 、 and into respectively to obtain the corresponding three eigenvectors 、 and ;

[0026] wherein T is the corresponding magnetic gradient tensor matrix, and E is a three-order unit matrix.

[0027] As preferred, in obtaining the corresponding three eigenvectors 、 and , the following constraint condition is constructed,

[0028] ;

[0029] ;

[0030] ;

[0031] wherein, 、 、 、 are the magnetic field amplitudes at the first to fourth measurement points respectively, is the magnetic field vector at the center point of the four measurement points.

[0032] As preferred, the eigenvector corresponding to the eigenvalue of 0 is taken as the spatial direction vector of the overhead transmission line to be measured.

[0033] As preferred, based on the two eigenvectors corresponding to the two opposite eigenvalues, the direction vector of the center point of the four measurement points pointing to the overhead transmission line to be measured is obtained.

[0034] In one overhead transmission line positioning system of the present disclosure, a magnetic sensor matrix device for three-dimensional magnetic field measurement and a processing device are included;

[0035] wherein,

[0036] The magnetic sensor matrix device for three-dimensional magnetic field measurement is used to obtain at least one set of three-axis magnetic field measurement data at the space adjacent to the overhead transmission line to be measured;

[0037] The processing device is used to perform any of the above overhead transmission line positioning methods.

[0038] The beneficial effects of the present disclosure include:

[0039] By constructing the magnetic gradient tensor matrix of the magnetic sensor array and solving the eigenvalues and eigenvectors thereof, high-precision non-contact positioning of the distance and direction of the transmission line can be achieved without prior current information; the method utilizes the suppression characteristics of the magnetic gradient tensor matrix on background noise and far-field interference, significantly improves the anti-interference ability and positioning robustness of the system in complex electromagnetic environments, and is suitable for transmission lines of different voltage levels and trends; not only is the sensor layout flexible and the calculation efficient, but also can meet the real-time requirements of unmanned aerial vehicle inspection, and provides a reliable position sensing means for unmanned aerial vehicle autonomous flight along the line, effectively solving the key technical bottleneck in intelligent transmission line inspection, and having good engineering application prospect and significant social and economic benefits. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 is a structural schematic diagram of a magnetic sensor matrix device of the present disclosure;

[0041] Figure 2 A schematic diagram of a structure of a support of the present disclosure;

[0042] Figure 3 A schematic diagram of a structure of a single-layer magnetic measurement matrix device of the present disclosure;

[0043] Figure 4 A block diagram of a measurement matrix circuit of the present disclosure;

[0044] Figure 5 A circuit diagram of an interface circuit of the present disclosure;

[0045] Figure 6 A circuit diagram of a power supply circuit of the present disclosure;

[0046] Figure 7 A circuit diagram of a three-axis magnetic sensor circuit of the present disclosure;

[0047] Figure 8 A schematic diagram of a calculation model of a spatial distance between any two three-dimensional magnetic measurement units 121 of the present disclosure;

[0048] Figure 9 A deployment diagram of measurement points when a set of three-axis magnetic field measurement data is provided by four magnetic sensors in the present disclosure;

[0049] Figure 10 A deployment diagram of measurement points when a set of three-axis magnetic field measurement data is provided by five magnetic sensors in the present disclosure. DETAILED DESCRIPTION

[0050] For a further understanding of the present disclosure, reference will be made to the following examples. It will be appreciated that these examples are intended to explain the present disclosure and are not intended to limit the present disclosure in any manner.

[0051] As shown in Figures 1-3 , the present disclosure provides a magnetic sensor matrix device for three-dimensional magnetic field measurement of overhead lines, which comprises a device body 100, the device body 100 comprising a support 110, the support 110 being provided with a plurality of single-layer magnetic measurement matrix devices 120 arranged in a uniform interval in the height direction; a plurality of three-dimensional magnetic measurement units 121 are arranged in a rectangular array at the single-layer magnetic measurement matrix device 120, the plurality of three-dimensional magnetic measurement units 121 having the same column spacing and the same row spacing, and the corresponding three-dimensional magnetic measurement units 121 at the plurality of single-layer magnetic measurement matrix devices 120 being aligned in the height direction.

[0052] Wherein, the array spacing between any two three-dimensional magnetic measurement units 121 satisfies the following conditions,

[0053] ​

[0054] wherein, is a required difference value of the magnetic field intensity measurement values of any two three-dimensional magnetic measurement units 121 when the device body 100 remains stationary, is the vacuum permeability, I is the carrying current at the DC bus, R is the spatial distance of the forward DC bus and the reverse DC bus, and r is the spatial distance of the device body 100 and the nearest DC bus.

[0055] Based on the above, the construction of an N x Q order magnetic sensing matrix can be achieved by arranging N x Q (N and Q are not less than 2) three-dimensional magnetic measurement units 121 at each single-layer magnetic measurement matrix device 120, and the precise measurement of the three-dimensional magnetic field can be achieved by arranging M layers (M is not less than 2) of single-layer magnetic measurement matrix devices 120 in a spaced stacked manner in the height direction; wherein each three-dimensional magnetic measurement unit 121 can be modularly packaged to maintain consistency, and the expansion and replacement of the magnetic sensing matrix device can be quickly achieved by increasing or decreasing the number of single-layer magnetic measurement matrix devices 120.

[0056] Through the scheme of the present disclosure, high-precision measurement and dynamic acquisition of the local three-dimensional magnetic field around the overhead transmission line can be achieved, which effectively solves the technical problem of real-time and stable perception of the magnetic field around the transmission line during the flight of the unmanned aerial vehicle, significantly improves the integrity and reliability of the magnetic field data in complex spatial environments; the obtained three-dimensional magnetic field distribution data not only provides strong support for analyzing the local magnetic field distribution characteristics of the transmission line, but also lays a technical foundation for identifying the position and orientation of the transmission line based on the magnetic field distribution characteristics, and effectively promotes the development and engineering application of unmanned aerial vehicle autonomous inspection technology.

[0057] As shown in Figure 2 The bracket 110 includes a bracket body of insulating material, the bracket body has a mounting frame composed of a plurality of cross bars 210 connected end to end in sequence, and a stand 210 for connecting the mounting frame in the height direction; a plurality of positioning columns 211 are arranged inside the mounting frame, the upper end surfaces of the plurality of positioning columns 211 collectively form a mounting plane for mounting the corresponding single-layer magnetic measurement matrix device 120; a lug 230 is arranged at the upper end of the bracket body.

[0058] Through the above structure, an exoskeleton type mountable lightweight structure can be formed, which is suitable for unmanned aerial vehicle mounting application; wherein the bracket body of insulating material can better avoid interlayer electrical coupling and will not affect the internal magnetic field of the measurement device; the mounting frame can better realize the replacement, increase and decrease of the single-layer magnetic measurement matrix device 120, and the adjustment of the layer spacing of the single-layer magnetic measurement matrix device 120.

[0059] As shown in Figure 3As shown, the single-layer magnetic measurement matrix device 120 includes a PCB circuit board 310 and a measurement matrix circuit printed on the PCB circuit board 310, and the PCB circuit board 310 is used to be mounted at a mounting plane; the measurement matrix circuit includes three-axis magnetic sensor circuits 320 corresponding to the three-dimensional magnetic measurement units 121 and an interface circuit 330, and the interface circuit 330 is used to realize data transmission and power supply access between the host computer and all the three-axis magnetic sensor circuits 320.

[0060] Through the above, an independent interface circuit 330 can be arranged at each single-layer magnetic measurement matrix device 120, data linkage and power supply connection between all the three-dimensional magnetic measurement units 121 at each single-layer magnetic measurement matrix device 120 and the host computer are realized, so that the interfaces of each layer are independent of each other and are not connected with each other, and the host computer can use a multi-channel parallel acquisition mode to perform parallel sampling on different layers, which is beneficial to data transmission.

[0061] Among them, the PCB circuit board 310 is provided with a hollow region 311. Therefore, the self-weight and wind resistance of the device body 100 can be preferably reduced, which is beneficial to unmanned aerial vehicle mounting application.

[0062] In combination Figure 4 As shown, the interface circuit 330 is provided with a power supply circuit, and the power supply circuit is used to obtain power supply from the host computer through the interface circuit 330 and supply power to all the three-axis magnetic sensor circuits 320. Based on this, the power supply source can supply power to each three-axis magnetic sensor circuit 320 in a star-shaped layout after being processed by the power supply circuit, which effectively reduces the channel crosstalk and the voltage drop difference caused by uneven current path.

[0063] In combination Figure 5 As shown, the interface circuit 330 includes a multi-core plug connector, and the interface pins of the multi-core plug connector are configured to include a ground pin GND, a power supply pin VCC, a signal pin and a clock signal pin SCL. It can be understood that the number of signal pins can be consistent with the number of three-dimensional magnetic measurement units 121 at each single-layer magnetic measurement matrix device 120.

[0064] In combination Figure 6 As shown, the output end of the power supply circuit is provided with a decoupling network, and the decoupling network includes capacitors C2, C3 and C4. Based on this, the power supply stability and channel consistency can be improved.

[0065] In combination Figure 7 As shown, the three-axis magnetic sensor circuit 320 can include a three-axis magnetic sensor and its peripheral circuit, and the model of the three-axis magnetic sensor can be selected as QMC5883P.

[0066] In which, since the same I2C address is set for the triaxial magnetic sensor chip when it is shipped, in order to save resources, the same layer adopts the time-division multiplexing I2C architecture. The whole layer shares one SCL clock line, which is preferentially routed along the board edge trunk, and pull-up and test pads are set at necessary positions; each magnetic measurement module is configured with an independent SDA special line, which is directly led from the module pad to the multi-core connector of the layer, so as to reduce the number of buses and avoid the risk of address conflict.

[0067] In one preferred embodiment of the present disclosure, the spatial distance between any two three-dimensional magnetic measurement units 121 is 80 mm.

[0068] In combination with Figure 8 , R is the horizontal distance between positive and negative conductors, r is the distance between the unmanned aerial vehicle and the conductor, Δs is the distance between the two magnetic field measurement points, the carrying current of the positive direct current bus and the negative direct current bus is I (the effective value of the alternating current bus current is I), the magnetic field intensity generated by the carrying current of the positive direct current bus at the magnetic field measurement point ① is B1, the magnetic field intensity generated at the magnetic field measurement point ② is B2, the magnetic field intensity generated by the carrying current of the negative direct current bus at the magnetic field measurement point ① is B3, and the magnetic field intensity generated at the magnetic field measurement point ② is B4, then the calculation formula of the difference ΔB of the magnetic field intensities generated by the positive and negative direct current buses at the magnetic field measurement point ① and the magnetic field measurement point ② is,

[0069] ;

[0070] Further, it can be obtained that,

[0071] .

[0072] When the unmanned aerial vehicle usually patrols the high-voltage transmission line, the safety distance is about 10 meters; the measurement accuracy of the magnetic measurement chip is 0.0133 μT, and ΔB is at least 10 times the measurement accuracy, i.e., ΔB≥0.133 μT. The current I is generally in the range of 1000 A~4000 A, and from the above formula, the magnetic sensor spacing is inversely proportional to the current, so I is considered to be 1000 A. By substituting R=20 m, r=10 m, ΔB≥0.133 μT, and I=1000 A into the formula, Δs≥0.075 m, so the row spacing and column spacing of the magnetic measurement matrix unit are 0.08 m. In fact, the appropriate value range is preferably within [50 mm, 100 mm].

[0073] ​​​Through constructing a high-voltage transmission line magnetic field simulation model, simulation shows that: in the case of current 4000A, at a position 10 meters away from the transmission line, when the magnetic sensor interval is 50mm, the magnetic field strength changes only 0.35μT; when the magnetic sensor interval is 80mm, the magnetic field strength changes 0.56μT; when the magnetic sensor interval is 100mm, the magnetic field strength changes 0.7μT.

[0074] Based on any one of the three-dimensional magnetic field measurement magnetic sensor matrix devices of the application, the application also provides an overhead transmission line positioning system.

[0075] The overhead transmission line positioning method comprises the following steps,

[0076] Obtaining at least one set of three-axis magnetic field measurement data at the space adjacent to the overhead transmission line to be measured; wherein one set of three-axis magnetic field measurement data comprises three-axis magnetic field measurement data of four measurement points arranged in a square array at the same plane.

[0077] For any one set of three-axis magnetic field measurement data, a magnetic gradient tensor matrix of the center point corresponding to the four measurement points is constructed.

[0078] Obtaining the ratio of the magnetic field amplitude of the center point corresponding to the four measurement points to the spectral norm of the corresponding magnetic gradient tensor matrix, and obtaining the distance between the overhead transmission line to be measured and the center point corresponding to the four measurement points as the distance data of the overhead transmission line to be measured.

[0079] Obtaining three eigenvectors of the corresponding magnetic gradient tensor matrix, and obtaining the spatial direction vector of the overhead transmission line to be measured as the trend data of the overhead transmission line to be measured.

[0080] Through the above method, based on the four measurement points arranged in a "cross" array in the same set of three-axis magnetic field measurement data, the magnetic gradient tensor matrix of the center point can be constructed by using the finite difference method, and the distance and direction positioning of the transmission line can be realized by analyzing the eigenvalues and eigenvectors of the magnetic gradient tensor matrix; the method has the advantages of simple data processing, compact implementation structure, high positioning accuracy, and can effectively suppress the geomagnetic field interference, is suitable for transmission line positioning in unmanned aerial vehicle power inspection, and has good engineering application value.

[0081] It can be understood that the adjacent space of the to-be-measured overhead transmission line refers to the inspection range of the unmanned aerial vehicle, which is related to the detection range of the magnetic sensing matrix device for three-dimensional magnetic field measurement.

[0082] wherein, when the number of groups of the at least one group of three-axis magnetic field measurement data is not less than 1, distance data and trend data of the to-be-measured overhead transmission line are obtained based on distances between the to-be-measured overhead transmission line corresponding to each group of three-axis magnetic field measurement data and center points of the corresponding four measurement points and a spatial direction vector of the to-be-measured overhead transmission line.

[0083] Based on this, the data obtained by each group of three-axis magnetic field measurement data can be cross-checked, and the mean or synthetic quantity of the data obtained by each group of three-axis magnetic field measurement data can be used as the final data output, so that the detection accuracy and anti-interference of the data can be better improved.

[0084] It can be understood that when there is not less than one group of three-axis magnetic field measurement data, since the distance data of the to-be-measured overhead transmission line is the distance between the to-be-measured overhead transmission line and the center points of the corresponding four measurement points, a fixed reference point can be selected, the distances between the to-be-measured overhead transmission line and the center points of the corresponding four measurement points of each group are converted to the distances between the to-be-measured overhead transmission line and the reference point, and then the mean of the data obtained by each group is calculated, and thus the distance data of the to-be-measured overhead transmission line can be obtained.

[0085] It can be understood that when there is not less than one group of three-axis magnetic field measurement data, the unit vectors of the spatial direction vectors of the to-be-measured overhead transmission line obtained by each group can be synthesized, and thus the trend data of the to-be-measured overhead transmission line can be obtained.

[0086] wherein, for any group of three-axis magnetic field measurement data, the magnetic gradient tensor matrix of the center points of the corresponding four measurement points constructed is,

[0087] ;

[0088] wherein, d is the diagonal distance of the four measurement points, 、 and is the magnetic field measurement data of one of the four measurement points on the x-axis, y-axis and z-axis, 、 and is the magnetic field measurement data of the second of the four measurement points on the x-axis, y-axis and z-axis, 、 and is the magnetic field measurement data of the third of the four measurement points on the x-axis, y-axis and z-axis, 、 and the magnetic field measurement data on the x-axis, the y-axis and the z-axis of the fourth one of the four measurement points;

[0089] wherein the one and the third of the four measurement points are diagonally distributed, and the second and the fourth of the four measurement points are diagonally distributed.

[0090] Based on the above, the partial derivative can be approximated by using the finite difference method, the magnetic gradient tensor matrix T is constructed, and the expression of the magnetic gradient tensor at the center point based on the three-axis magnetic field data at the four end points is completed, which is simple and easy to implement and conducive to data processing.

[0091] It can be understood that the array spacing .

[0092] wherein for any set of three-axis magnetic field measurement data, the magnetic field amplitude of the center point corresponding to the four measurement points is obtained by measurement or based on the average of the three-axis magnetic field measurement data corresponding to the four measurement points.

[0093] as shown in Figure 9 , a deployment diagram of four measurement points when providing a set of three-axis magnetic field measurement data by using four magnetic sensors (three-dimensional magnetic measurement unit 121); under this deployment mode, the calculation method of the magnetic field amplitude of the center point corresponding to the four measurement points can be,

[0094] .

[0095] as shown in Figure 10 , a deployment diagram of four measurement points when providing a set of three-axis magnetic field measurement data by using five magnetic sensors (three-dimensional magnetic measurement unit 121); wherein the fifth magnetic sensor (three-dimensional magnetic measurement unit 121) is arranged at the center point corresponding to the four measurement points; under this deployment mode, the calculation method of the magnetic field amplitude of the center point corresponding to the four measurement points can be,

[0096] .

[0097] wherein for any set of three-axis magnetic field measurement data, the spectral norm of the corresponding magnetic gradient tensor matrix is obtained by the steps of,

[0098] obtaining three eigenvalues , and of the corresponding magnetic gradient tensor matrix; wherein and are opposite numbers, is 0;

[0099] The spectral norm of the corresponding magnetic gradient tensor matrix is the absolute value of the maximum eigenvalue.

[0100] The spectral norm of the corresponding magnetic gradient tensor matrix is the absolute value of the maximum eigenvalue.

[0101] .

[0102] wherein, for any set of three-axis magnetic field measurement data, based on 3 eigenvalues , and of the corresponding magnetic gradient tensor matrix, 3 eigenvectors , and of the corresponding magnetic gradient tensor matrix are obtained, specifically,

[0103] the 3 eigenvalues , and are substituted into respectively to obtain the corresponding 3 eigenvectors , and ;

[0104] wherein, T is the corresponding magnetic gradient tensor matrix, and E is a three-order unit matrix.

[0105] It can be understood that the eigenvector is consistent with the current direction in the to-be-measured overhead transmission line, and the direction vector of the to-be-measured overhead transmission line pointing to the center point of the corresponding 4 measurement points and the eigenvectors and all form a 45° angle.

[0106] wherein, when the corresponding 3 eigenvectors , and are obtained, the following constraint conditions are constructed,

[0107] ;

[0108] ;

[0109] ;

[0110] wherein, , , , are the magnetic field amplitudes at the one to the four of the 4 measurement points respectively, is a magnetic field vector of a center point of the corresponding 4 measurement points. ​

[0111] Based on the above, the ambiguity of the eigenvectors can be eliminated in the process of solving the three eigenvectors of the magnetic gradient tensor matrix.

[0112] Among them, the eigenvector corresponding to the eigenvalue of 0 is taken as the spatial direction vector of the overhead transmission line to be measured.

[0113] Among them, the eigenvector corresponding to the eigenvalue of 0 is taken as the spatial direction vector of the overhead transmission line to be measured.

[0114] Based on the above positioning method, the magnetic gradient tensor matrix of the magnetic sensor array can be constructed, and the eigenvalues and eigenvectors thereof can be solved, so that high-precision non-contact positioning of the transmission line distance and direction can be realized without prior current information. The method utilizes the suppression characteristics of the magnetic gradient tensor matrix to background noise and far-field interference, significantly improves the anti-interference ability and positioning robustness of the system in complex electromagnetic environment, and is suitable for transmission lines of different voltage levels and trends. Not only is the sensor layout flexible and the calculation efficient, but it can also meet the real-time requirements of unmanned aerial vehicle inspection, and provides a reliable position sensing means for unmanned aerial vehicle autonomous flight along the line, effectively solving the key technical bottleneck in intelligent transmission line inspection, and having good engineering application prospect and significant social and economic benefits.

[0115] As a further illustration, a set of specific example data is given based on the deployment mode of Figure 10 In the laboratory conditions, a straight wire is powered with a current direction of [0.05, -0.05, 1], and a cross-sensor array composed of 5 magnetic sensors is as shown in Figure 10 , wherein the distance d between M1 and M3, M2 and M4 is 0.056 m, the distance r from M5 to the straight wire is 0.1 m, and the data measured by the cross-sensor array is shown in the following table.

[0116] Measurement point x-axis magnetic field measurement data B x / μT [CAT] y-axis magnetic field measurement data B y / μT z-axis magnetic field measurement data B z / μT M1 52.843 135.575 4.136 M2 41.525 191.187 7.483 M3 131.132 188.095 2.848 M4 97.310 124.310 1.350 M5 80.159 160.319 4.008

[0117] Based on the above data, the magnetic gradient tensor matrix at the center point M5 is

[0118] ;

[0119] The corresponding three eigenvalues are

[0120] ,

[0121] ,

[0122] ;

[0123] The eigenvectors corresponding to the three eigenvalues are,

[0124] ,

[0125] ,

[0126] ;

[0127] The magnetic field amplitude at the center point M5 is,

[0128] ;

[0129] The distance from the center point M5 to the wire is,

[0130] ;

[0131] The direction vector of the center point M5 to the wire is,

[0132] ;

[0133] The direction vector of the wire is,

[0134] [0.050, -0.060, 0.996].

[0135] Based on the above example data, it can be verified that the method of the present disclosure has high positioning accuracy when positioning the wire.

[0136] The above description of the present application and its embodiments is illustrative and not restrictive, and the examples shown are only part of the embodiments of the present application, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it, without departing from the spirit of the present application, similar structural forms and examples can be designed without creative design, which should belong to the protection scope of the present application.

[0137] It is easy to understand that, based on one or more embodiments provided in the present application, a person skilled in the art can combine, split, recombine, etc. to obtain other embodiments, and these embodiments do not exceed the protection scope of the present application.

Claims

1. A method for locating overhead transmission lines, comprising, Acquire at least one set of triaxial magnetic field measurement data at the space adjacent to the overhead transmission line under test; wherein, one set of triaxial magnetic field measurement data includes triaxial magnetic field measurement data of 4 measurement points, and the 4 measurement points are distributed in a square array on the same plane; For any set of triaxial magnetic field measurement data, a magnetic gradient tensor matrix corresponding to the center point of the four measurement points is constructed. Obtain the ratio of the magnetic field amplitude at the center point of the four corresponding measurement points to the spectral norm of the corresponding magnetic gradient tensor matrix, and obtain the distance between the overhead transmission line under test and the center point of the four corresponding measurement points as the distance data of the overhead transmission line under test. Obtain the three eigenvectors of the corresponding magnetic gradient tensor matrix, obtain the spatial direction vector of the overhead transmission line under test, and obtain the direction data of the overhead transmission line under test.

2. The overhead transmission line positioning method according to claim 1, characterized in that: When the number of sets of at least one set of triaxial magnetic field measurement data is not less than 1, the distance data and direction data of the overhead transmission line under test are obtained based on the distance between the center point of the overhead transmission line under test and the corresponding four measurement points corresponding to each set of triaxial magnetic field measurement data, and the spatial direction vector of the overhead transmission line under test.

3. The overhead transmission line positioning method according to claim 1, characterized in that: For any set of triaxial magnetic field measurement data, the constructed magnetic gradient tensor matrix corresponding to the center points of the four measurement points is: ； Where d is the diagonal distance between the four measurement points. , and The magnetic field measurement data of one of the four measurement points on the x-axis, y-axis, and z-axis are provided. , and The magnetic field measurement data of two of the four measurement points on the x-axis, y-axis, and z-axis are given. , and The magnetic field measurement data for three of the four measurement points on the x-axis, y-axis, and z-axis are given. , and The magnetic field measurement data of four of the four measurement points on the x-axis, y-axis, and z-axis; Among them, one and three of the four measurement points are diagonally distributed, and the second and fourth of the four measurement points are diagonally distributed.

4. The overhead transmission line positioning method according to claim 1, characterized in that: For any set of triaxial magnetic field measurement data, the magnetic field amplitude at the center point of the corresponding four measurement points is obtained by measurement or based on the average of the triaxial magnetic field measurement data of the corresponding four measurement points.

5. The overhead transmission line positioning method according to claim 1, characterized in that: For any set of triaxial magnetic field measurement data, the steps to obtain the spectral norm of the corresponding magnetic gradient tensor matrix include: Obtain the three eigenvalues ​​of the corresponding magnetic gradient tensor matrix. , and ;in, and They are opposites. =0; The spectral norm of the corresponding magnetic gradient tensor matrix is ​​the absolute value of the largest eigenvalue.

6. The overhead transmission line positioning method according to claim 5, characterized in that: For any set of triaxial magnetic field measurement data, based on the three eigenvalues ​​of the corresponding magnetic gradient tensor matrix... , and Obtain the three eigenvectors of the corresponding magnetic gradient tensor matrix. , and , specifically, 3 eigenvalues , and Substitute them separately Obtain the corresponding 3 feature vectors , and ; Where T corresponds to the magnetic gradient tensor matrix, and E is the third-order identity matrix.

7. The overhead transmission line positioning method according to claim 6, characterized in that: After obtaining the corresponding 3 feature vectors , and At that time, the following constraints are constructed. ； ； ； in, , , , These are the magnetic field amplitudes at one to four of the four measurement points. This is the magnetic field vector corresponding to the center point of the four measurement points.

8. The overhead transmission line positioning method according to claim 7, characterized in that: The eigenvector with a corresponding eigenvalue of 0 is used as the spatial direction vector of the overhead transmission line under test.

9. The overhead transmission line positioning method according to claim 7, characterized in that: Based on the two eigenvectors of the two eigenvalues ​​corresponding to opposite numbers, the direction vectors pointing from the center point of the four measurement points to the overhead transmission line under test are obtained.

10. An overhead transmission line positioning system, characterized in that: Includes a magnetic sensing matrix device and processing device for three-dimensional magnetic field measurement; in, A magnetic sensing matrix device for three-dimensional magnetic field measurement is used to acquire at least one set of three-axis magnetic field measurement data in the space adjacent to the overhead transmission line under test. The processing device is used to perform the overhead transmission line positioning method according to any one of claims 1-9.

Images