Electromagnetic base station and pipeline positioning system

Abstract

The invention discloses an electromagnetic base station and a pipeline positioning system, and belongs to the technical field of pipeline detection. The electromagnetic base station is applied to the pipeline positioning system. The electromagnetic base station comprises a power supply module and a wire. Two ends of the wire are respectively connected with two ends of the power supply module to form a detection loop; a part of wires in the detection loop are used as measuring wires; wherein the power supply module is used for providing alternating current for the wire; the measuring wire is placed in an area above the pipeline to be measured, and the measuring wire is used for generating a reference alternating magnetic field required by pipeline positioning when the alternating current circulates. According to the embodiment of the invention, the alternating magnetic field can be provided, and the coordinates of the inner detector can be accurately positioned, so that accurate pipeline positioning is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of pipeline detection, and in particular, to an electromagnetic base station and a pipeline positioning system. Background Art

[0002] As the "lifeline project" of modern cities, the safety of urban pipe networks is crucial for the normal operation of social production and life. Since most pipelines are installed underground, they have the characteristics of long pipeline lengths and complex covering conditions, making pipeline positioning a complex and important problem. Moreover, many pipelines are made of non-metallic materials, which are non-conductive and non-magnetic, further increasing the difficulty of pipeline positioning. Taking polyethylene (PE) pipelines as an example, PE pipelines have the advantages of good flexibility, strong corrosion resistance, and light weight, and are widely used in urban water supply and gas transportation. Buried PE pipe networks play a very important role in urban safety and residents' living security. Therefore, it is necessary to master the accurate position information of buried PE pipe networks to avoid damage to pipelines caused by excavation and other external forces, resulting in safety accidents. Due to the good insulation of polyethylene materials, they do not generate other easily measurable signals such as light, sound, magnetism, electricity, and heat, and their positioning difficulty is much greater than that of ferromagnetic pipelines. Therefore, it is very important to accurately obtain the position information of buried PE pipelines and eliminate construction hazards caused by the lack of position information.

[0003] Currently, common pipeline positioning methods include the electronic marking method, the tracer wire method, the ground penetrating radar method, the acoustic method, and the inertial navigation method, etc. However, the electronic marking method and the tracer wire method require detecting devices to be pre-laid around or inside the pipeline when laying the pipeline; the ground penetrating radar method and the acoustic method have high requirements for the environment and road surface flatness, and it is difficult to achieve pipeline positioning in complex environments; the inertial navigation method needs to cut the pipeline during measurement and cannot achieve the positioning of in-service pipelines. Therefore, the above measurement methods cannot well achieve the coordinate measurement of pipelines.

[0004] At the same time, as a new type of pipeline internal detection device, the internal detector has a diameter smaller than the pipe diameter and can move forward under the driving action of the fluid in the pressure pipeline, recording positioning-related information along the way, which is conducive to portable pipeline positioning. However, due to the mobile detection of the internal detector, its attitude is very unstable when moving in the pipeline, and there is electromagnetic shielding in the water-containing soil above the buried pipeline, and there is also magnetic interference from the steel bars of urban buildings, etc. Therefore, it is difficult to accurately position using inertial navigation, satellites, and geomagnetism. Therefore, there is an urgent need for a technology that can accurately position the coordinates of the pipeline internal detector. Summary of the Invention

[0005] The present invention provides an electromagnetic base station and a pipeline positioning system to provide an alternating magnetic field, which is conducive to accurately positioning the coordinates of the internal detector, thereby achieving accurate pipeline positioning.

[0006] In a first aspect, an embodiment of the present invention provides an electromagnetic base station, which is applied to a pipeline positioning system;

[0007] The electromagnetic base station includes: a power supply module and a wire; both ends of the wire are respectively connected to both ends of the power supply module to form a detection loop; at least part of the wire in the detection loop serves as a measurement wire;

[0008] Wherein, the power supply module is used to provide an alternating current to the wire; the measurement wire is placed in the upper area of the pipeline to be measured, and the measurement wire is used to generate a reference alternating magnetic field required for pipeline positioning when the alternating current flows through it; when an internal detector in the pipeline positioning system passes through the interior of the pipeline to be measured, it collects the reference alternating magnetic field to achieve pipeline positioning.

[0009] Optionally, the power supply module includes:

[0010] A DC power supply;

[0011] A current direction adjustment unit, connected between the DC power supply and the wire;

[0012] A control unit, connected to the current direction adjustment unit, for controlling the connection state between the DC power supply and the wire through the current direction adjustment unit to control the current direction provided to the wire.

[0013] Optionally, the current direction adjustment unit includes:

[0014] A first switch, connected between the positive pole of the DC power supply and one end of the power supply module;

[0015] A second switch, connected between the positive pole of the DC power supply and the other end of the power supply module;

[0016] A third switch, connected between the negative pole of the DC power supply and one end of the power supply module;

[0017] A fourth switch; connected between the negative pole of the DC power supply and the other end of the power supply module;

[0018] The control unit is respectively connected to the control ends of the first switch, the second switch, the third switch and the fourth switch;

[0019] And / or, the control unit includes a single-chip microcomputer;

[0020] And / or, the power supply module further includes: an ammeter, arranged at any end of the power supply module, for collecting the current in the detection loop.

[0021] Optionally, the amplitude of the voltage output by the power supply module is less than or equal to the human body safety voltage threshold;

[0022] The amplitude of the alternating current is greater than or equal to a preset current amplitude; wherein, the preset current amplitude is determined according to the perpendicular distance between the measurement wire and the pipeline to be measured, and the detection sensitivity of the magnetometer in the internal detector of the pipeline positioning system;

[0023] The length, material, and cross-sectional area of the wire are determined according to the amplitude of the voltage output by the power supply module and the amplitude of the alternating current.

[0024] Optionally, the frequency range of the alternating current is: 1 Hz - 40 Hz;

[0025] And / or, the frequency of the alternating current is not an integer multiple of the power frequency.

[0026] Optionally, part of the wire in the detection loop serves as the measurement wire, and the other wires in the detection loop include interference segments with a current direction opposite to that of the current in the measurement wire;

[0027] The distance between the measurement wire and the interference segment is greater than a first preset distance; wherein, the greater the amplitude of the current provided by the power supply module to the detection loop, the greater the first preset distance.

[0028] In a second aspect, an embodiment of the present invention further provides a pipeline positioning system, including: an internal detector, a host computer, and the electromagnetic base station provided in any embodiment of the present invention;

[0029] The internal detector is configured to collect magnetic field information when passing through the pipeline to be measured;

[0030] The host computer is configured to determine the positioning result of the pipeline to be measured according to the reference alternating magnetic field emitted by the electromagnetic base station and the magnetic field information collected by the internal detector.

[0031] Optionally, the pipeline to be measured includes multiple segments to be measured, and at least one of the electromagnetic base stations is correspondingly arranged in the upper region of each segment to be measured;

[0032] The difference between the frequencies of the alternating currents in any two of the electromagnetic base stations corresponding to adjacent two of the segments to be measured is greater than or equal to a preset frequency difference;

[0033] And / or, the difference between the frequencies of the alternating currents in any two of the electromagnetic base stations corresponding to the same segment to be measured is greater than or equal to a preset frequency difference.

[0034] Optionally, for any two of the electromagnetic base stations with different frequencies of the alternating current, the frequencies of the alternating currents in the two electromagnetic base stations are not integer multiples of each other.

[0035] Optionally, the wire in the electromagnetic base station is laid on the ground above the pipeline to be measured;

[0036] Alternatively, the pipeline positioning system further includes: an overhead structure, and the wire in the electromagnetic base station is arranged on the water surface above the pipeline to be measured through the overhead structure.

[0037] Optionally, the pipeline positioning system further includes: a wire positioning device connected to the host computer; the wire positioning device is used to obtain the layout information of the wire in the electromagnetic base station; the host computer is further used to determine the reference alternating magnetic field emitted by the electromagnetic base station according to the layout information of the wire.

[0038] Optionally, the pipeline positioning system further includes:

[0039] A delivery device, arranged at the starting position of the pipeline to be measured, for delivering the internal detector into the pipeline to be measured;

[0040] A receiving device, arranged at the end position of the pipeline to be measured, for recovering the internal detector in the pipeline to be measured.

[0041] In the electromagnetic base station provided by the embodiment of the present invention, an alternating current is provided to the wire through a power supply module, so that the measurement wire generates a reference alternating magnetic field required for pipeline positioning. Among them, the alternating magnetic field is different from the basically constant geomagnetic field and can be reliably and accurately separated from the magnetic field information collected by the internal detector for pipeline positioning. And by adjusting the amplitude of the alternating current provided by the power supply module, the intensity of the reference alternating magnetic field can be conveniently adjusted. On the one hand, it is beneficial to meet the magnetic field intensity requirements for magnetic field collection by the internal detector at any depth. On the other hand, it can be applied to pipeline positioning in various complex environments and reduce the influence of various magnetic interferences. And because the wire itself has the characteristic of being easy to fold and can be arranged in different shapes, it is also beneficial to improve the versatility and flexibility of the electromagnetic base station in various scenarios and facilitate the movement of the electromagnetic base station. Furthermore, setting the electromagnetic base station with an energized wire as the emission source can make the electromagnetic base station efficient and low-power. In summary, the electromagnetic base station provided by the embodiment of the present invention can provide a reference alternating magnetic field, which is beneficial to accurately positioning the coordinates of the internal detector, thereby realizing accurate pipeline positioning.

[0042] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. Description of the Drawings

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0044] Figure 1 It is a schematic structural diagram of an electromagnetic base station provided by an embodiment of the present invention;

[0045] Figure 2 It is a schematic waveform diagram of an alternating current provided by an embodiment of the present invention;

[0046] Figure 3 It is a diagram of the magnetic field measurement results of a reference alternating magnetic field 20 m away from the measurement wire provided by an embodiment of the present invention;

[0047] Figure 4 It is a schematic structural diagram of a pipeline positioning system provided by an embodiment of the present invention. Specific embodiments

[0048] In order to enable those skilled in the art to better understand the solutions of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0049] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above accompanying drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order different from those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion.

[0050] An embodiment of the present invention provides an electromagnetic base station, which is applied to a pipeline positioning system and can generate an alternating magnetic field different from the geomagnetic field to form a reference alternating magnetic field required for pipeline positioning. When the internal detector in the pipeline positioning system passes through the interior of the pipeline to be measured, it continuously collects magnetic field information during the forward process. By comparing and matching the magnetic field information detected by the internal detector with the reference alternating magnetic field generated by the electromagnetic base station, the positioning of the pipeline can be obtained. Among them, the electromagnetic base station can generate a three-dimensional alternating magnetic field. Correspondingly, the final positioning result obtained through magnetic field inversion is a three-dimensional positioning result, and the position offsets of the pipeline to be measured in the horizontal and vertical directions can be determined.

[0051] Figure 1 It is a schematic structural diagram of an electromagnetic base station provided by an embodiment of the present invention. Refer to Figure 1 , the electromagnetic base station 10 includes: a power supply module 11 and a wire 12. Both ends of the wire 12 are respectively connected to both ends of the power supply module 11 to form a detection circuit; at least part of the wire in the detection circuit serves as a measurement wire L1. Figure 1 Exemplarily, part of the wire in the detection circuit serves as the measurement wire L1. Among them, the power supply module 11 is used to provide an alternating current to the wire 12; the measurement wire L1 is placed in the upper area of the pipeline to be measured, and the measurement wire L1 is used to generate a reference alternating magnetic field required for pipeline positioning when an alternating current flows through it. When the internal detector in the pipeline positioning system passes through the interior of the pipeline to be measured, it collects the reference alternating magnetic field to achieve pipeline positioning.

[0052] Exemplarily, the power supply module 11 can output an alternating current in the form of a sine wave, a square wave or other forms. The power supply module 11 can be a separately provided portable energy storage module or a power conversion module for processing commercial power. The pipeline to be measured can be a buried pipeline, such as a gas pipeline.

[0053] The effective wire segment of the measurement wire L1 during the detection process serves as a detection loop and is used to generate the reference alternating magnetic field required for pipeline positioning. Placing the measurement wire L1 in the upper area of the pipeline to be measured can be understood as: the measurement wire L1 is laid directly above the laying position determined by the initial laying of the pipeline to be measured or directly above the position determined during the previous positioning, so that the amplitude of the alternating current flowing through the measurement wire L1 is minimized when the magnetic field intensity at the buried position of the pipeline to be measured reaches the magnetic field intensity requirement, thereby reducing the power consumption of the electromagnetic base station and enhancing the safety of pipeline positioning. Exemplarily, when the magnetic field intensity at the buried position of the pipeline to be measured reaches the magnetic field intensity requirement, it can be understood that when the internal detector passes through the inside of the pipeline to be measured, the magnetometer inside it can identify and collect the reference alternating magnetic field. Specifically, it can be described as: the modulus of the magnetic flux density of the reference alternating magnetic field emitted by the measurement wire L1 at the buried depth of the pipeline to be measured is greater than or equal to the preset magnetic flux density modulus. Among them, the buried depth of the pipeline to be measured can be determined according to the ground depth recorded during the initial laying of the pipeline to be measured or during the previous positioning. The preset magnetic flux density modulus can be determined according to the detection sensitivity of the magnetometer in the internal detector. For example, it is greater than or equal to the detection sensitivity of the magnetometer, so that the internal detector can sense and collect relevant information of the reference alternating magnetic field when passing through the inside of the pipeline to be measured.

[0054] In the electromagnetic base station provided by the embodiment of the present invention, an alternating current is provided to the wire 12 through the power supply module 11 to enable the measurement wire L1 to generate the reference alternating magnetic field required for pipeline positioning. Among them, the alternating magnetic field is different from the basically constant geomagnetic field and can be reliably and accurately separated from the magnetic field information collected by the internal detector for pipeline positioning. And by adjusting the amplitude of the alternating current provided by the power supply module 11, the intensity of the reference alternating magnetic field can be conveniently adjusted. On the one hand, it is beneficial to meet the magnetic field intensity requirements for magnetic field collection by the internal detector at any depth. On the other hand, it can be applied to pipeline positioning in various complex environments and reduce the influence of various magnetic interferences. Also, because the wire 12 itself has the characteristic of being easily foldable and can be arranged in different shapes, it is also beneficial to improve the versatility and flexibility of the electromagnetic base station in various scenarios and facilitate the movement of the electromagnetic base station 10. Moreover, setting the electromagnetic base station 10 with the energized wire as the emission source can make the electromagnetic base station 10 highly efficient and low in power consumption. In summary, the electromagnetic base station provided by the embodiment of the present invention can provide a reference alternating magnetic field, which is beneficial to accurately positioning the coordinates of the internal detector and thus realizing accurate pipeline positioning.

[0055] On the basis of the above embodiments, optionally, the amplitude of the alternating current is greater than or equal to a preset current amplitude, so that when the internal detector passes through the inside of the pipeline to be measured, the magnetometer therein can identify and collect the reference alternating magnetic field. Wherein, the preset current amplitude is determined according to the perpendicular distance between the measurement wire L1 and the pipeline to be measured, and the detection sensitivity of the magnetometer in the internal detector of the pipeline positioning system. For example, the magnetic field generated by the measurement wire L1 based on the preset current amplitude has a magnetic field strength greater than or equal to the detection sensitivity of the magnetometer at a distance equal to the above perpendicular distance from the measurement wire L1. Exemplarily, when the perpendicular distance is 20 m and the detection sensitivity of the magnetometer is at the nT level, the modulus of the magnetic flux density generated by the reference alternating magnetic field at a distance of 20 m from the measurement wire can be set to be not less than 0.1 μT.

[0056] On the basis of the above embodiments, optionally, the power supply module 11 provides an alternating voltage to the wire 12 to form an alternating current in the detection loop. Exemplarily, the amplitude of the voltage output by the power supply module 11 can be set to be less than or equal to the human body safety voltage threshold to ensure the safety of the electromagnetic base station 10.

[0057] On this basis, in practical applications, the upper limit of the overall resistance of the wire 12 can be determined according to the amplitude of the voltage output by the selected power supply module 11 and the amplitude of the required alternating current, and the length, material, and cross-sectional area of the wire 12 can be determined so that the resistance value of the wire does not exceed the resistance upper limit. Specifically, according to Ohm's law, the resistance of an energized wire is proportional to the length and resistivity and inversely proportional to the cross-sectional area. The length, material, and cross-sectional area of the wire 12 can be selected by comprehensively considering costs, the difficulty of bending / folding during wiring, and the coverage range of the magnetic field emitted by the electromagnetic base station 10. Exemplarily, a wire 12 with as long a length as possible can be selected to increase the coverage range of the magnetic field emitted by an electromagnetic base station 10, thereby reducing the number of electromagnetic base stations 10 required for positioning the entire pipeline to be measured.

[0058] Based on the above embodiments, optionally, when a part of the wires in the detection loop is used as the measurement wire L1, the other wires in the detection loop can be referred to as loop wires, and the loop wires are connected to the measurement wire L1 to form a complete current loop. Then, there will inevitably be an interference segment in the loop wire where the current direction is opposite to that in the measurement wire. To prevent the alternating magnetic field generated by the interference segment from canceling out the alternating magnetic field generated by the measurement wire L1 when an alternating current flows through the detection loop, resulting in insufficient magnetic field intensity at the buried depth of the pipeline to be measured, the distance between the interference segment and the measurement wire L1 can be controlled, that is, the distance (such as the perpendicular distance) between the measurement wire L1 and the interference segment is controlled to be greater than a first preset distance. The first preset distance is, for example, greater than the perpendicular distance between the measurement wire L1 and the pipeline to be measured, or the magnetic field intensity at a distance of the first preset distance from the interference segment generated by the interference segment can be set to be less than the detection sensitivity of the magnetometer. Among them, the greater the current amplitude provided by the power supply module 11 to the detection loop, the greater the first preset distance.

[0059] Exemplarily, the wire 12 can be arranged in a single-loop ring shape or a multi-loop spiral shape. It can be understood that both the ring shape and the spiral shape here are broad definitions. In addition to being an ellipse and a perfect circle, the contour of the ring shape and the contour of a single loop in the spiral shape can also be a quadrilateral, a polygon, or other irregular shapes. In this embodiment, there is no specific requirement for the shape of the contour of the ring shape and the contour of a single loop in the spiral shape, and it can be adjusted according to the on-site wiring situation, such as avoiding various obstacles on the site for wiring. When any segment of the wire 12 is used as the measurement wire L1, each segment with a current direction opposite to that of the measurement wire can be regarded as an interference segment.

[0060] In a specific embodiment, exemplarily, refer to Figure 1 , the detection loop can be in a quadrilateral shape, such as a rectangle or a parallelogram. One of the sides of the detection loop can be selected as the measurement wire L1. Among them, the side opposite to the measurement wire L1 in the detection loop is the interference segment. The distance d2 between the side opposite to the measurement wire L1 and the measurement wire L1 can be set to be greater than the first preset distance to prevent the magnetic fields generated by the interference segment and the measurement wire L1 from canceling each other out. The length d1 of the measurement wire L1 can be determined according to the total length of the wire 12 and the distance d2 between the side opposite to the measurement wire L1 and the measurement wire L1.

[0061] Exemplarily, the pipeline to be measured is a buried pipeline with a burial depth of 20 m. The wire 12 is arranged on the ground. The intensity requirement of the reference alternating magnetic field is that the modulus of the magnetic flux density generated at a depth of 20 m from the ground is not less than 0.1 μT. The amplitude of the alternating current satisfying this magnetic field intensity is greater than 28 A. Considering various magnetic interferences in the environment, the current can be appropriately increased to enhance the magnetic field intensity and ensure measurement accuracy. Then, the amplitude of the alternating current can be selected as ≥50 A, and the amplitude of the voltage output by the power supply module 11 is, for example, selected as 36 V. The detection loop can be rectangular, with dimensions of d1 = 50 m and d2 = 26 m. The wire 12 is selected as a copper wire with a cross-sectional area of 6 square millimeters. Then, the total length of the wire 12 is (50 + 26) × 2 = 152 m, and the resistance of the total wire loop is about 0.72 Ω, which can achieve the magnitude of the current amplitude required above.

[0062] Based on the above embodiments, optionally, the frequency range of the alternating current is: 1 Hz - 40 Hz to generate a low-frequency alternating magnetic field. Specifically, according to Maxwell's equations, the current frequency generated by the wire 12 is the same as the frequency of the spatial magnetic field, and the higher the frequency, the stronger the magnetic field attenuation of the environment on the wire 12. Considering comprehensively, the maximum frequency of the alternating current can be set not to exceed 40 Hz. For the lower limit value of the frequency range of the alternating current, it can be determined according to the following rules:

[0063] The internal detector is, for example, a spherical detector, which can roll inside the pipeline to be measured. The lower limit of the frequency range of the alternating current can be determined according to the rolling period of the internal detector and the signal acquisition frequency requirements. For example, when the internal detector rolls inside the pipeline to be measured, its rolling period is about 0.3 s - 0.5 s. Based on the positioning requirements, multiple complete cycles of magnetic field signals need to be collected during the single-circle rolling mileage of the sphere. Based on this, the frequency of the alternating current should not be lower than 1 Hz, preferably not lower than 5 Hz. Among them, the time for the internal detector to roll one circle is related to the diameter and weight of the internal detector itself, and the flow rate of the gas or liquid in the pipeline; the shorter the rolling period of the internal detector, the higher the lower limit value of the frequency range needs to be limited.

[0064] Based on the above embodiments, optionally, the frequency of the alternating current is not an integer multiple of the power frequency. Exemplarily, for the magnetic field information collected by the internal detector, according to the frequency characteristics, based on any signal decomposition algorithm, such as the VMD (Variational Modal Decomposition) algorithm, the magnetic field data corresponding to the frequency of the reference alternating magnetic field can be separated from the magnetic field information for comparison and matching with the actual distribution of the reference alternating magnetic field, so as to obtain the pipeline positioning. Denote the frequency of the reference alternating magnetic field as the target frequency. During the signal decomposition process, it may be necessary to separate the data related to the fundamental wave and multiple high-order harmonics of the target frequency from the magnetic field information and combine them to restore the magnetic field data of the target frequency. Among them, since there is a power frequency signal in the ground environment, such as power cables carrying 220V / 50Hz signals. If the frequency emitted by the electromagnetic base station is set to be an integer multiple of the power frequency, then the power frequency is the same as the frequency of one of the high-order harmonics of the frequency emitted by the electromagnetic base station. For example, if the frequency emitted by the electromagnetic base station is 10Hz, then the 50Hz power frequency signal is the same as the 5th harmonic of the signal emitted by the electromagnetic base station. In this case, when using the signal decomposition algorithm to separate the magnetic field information, modal aliasing will occur, so that the separated data related to the target frequency also includes interference data obtained from collecting the power frequency magnetic field. For example, it is impossible to distinguish the part belonging to the power frequency signal and the part belonging to the high-order harmonics of the reference alternating magnetic field in the separated 50Hz data, thus affecting the accuracy and reliability of the signal separation result. Therefore, setting the frequency of the alternating current to be not an integer multiple of the power frequency, for example, the frequency parameters such as 9Hz and 16Hz can be used for the frequency of the alternating current, which is beneficial to filtering out the power frequency interference during the signal separation process and retaining the integrity of the signals related to the reference alternating magnetic field.

[0065] Based on the above embodiments, optionally, there are various implementation manners of the power supply module 11. Several of them are exemplarily described below, but they do not limit the present invention.

[0066] In one embodiment, optionally, the power supply module 11 itself may adopt an AC power supply, such as a signal generator capable of outputting a sine signal.

[0067] In another embodiment, optionally, refer to Figure 1 , the power supply module 11 includes: a DC power supply E, a current direction adjustment unit 112, and a control unit 111. Among them, the current direction adjustment unit 112 is connected between the DC power supply E and the wire 12. The control unit 111 is connected to the current direction adjustment unit 112, and the control unit 111 is used to control the connection state between the DC power supply E and the wire 12 through the current direction adjustment unit 112 to control the current direction provided to the wire 12.

[0068] The alternating current provided by the power supply module 11 in this embodiment is a square wave signal with a certain duty cycle. Compared with direct current, less power consumption is required to generate an alternating current with the same amplitude. Exemplarily, the frequency of the alternating current is 9 Hz, and the waveform of the alternating current is as shown in Figure 2 shown. The positive and negative pulse widths of the alternating current can both be 30 ms, so the duty cycle of the alternating current is 30 * 2 / 111 = 54%. Among them, the positive and negative pulse widths in the alternating current are consistent, which is convenient for subsequent signal processing. The higher the duty cycle of the alternating current, the longer the duration that the alternating current maintains at the amplitude, and the longer the stable time of the magnetic field generated by the amplitude current, which is beneficial for the magnetometer to collect the magnetic field. Exemplarily, the duty cycle of the alternating current can be set by comprehensively considering the acquisition requirements and power consumption requirements of the magnetometer. The DC power supply E can be a DC power supply whose output voltage is less than or equal to the human body safety voltage threshold. For example, a switching power supply with a maximum output of 36 V is selected. The control unit 111 is, for example, a single-chip microcomputer.

[0069] Specifically, the current direction adjustment unit 112 may include: a first switch S1, a second switch S2, a third switch S3, and a fourth switch S4. The first switch S1 is connected between the positive pole of the DC power supply E and one end of the power supply module 11; the second switch S2 is connected between the positive pole of the DC power supply E and the other end of the power supply module 11; the third switch S3 is connected between the negative pole of the DC power supply E and one end of the power supply module 11; the fourth switch S4 is connected between the negative pole of the DC power supply E and the other end of the power supply module 11. The control unit 111 is respectively connected to the control terminals of the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4.

[0070] Among them, the positive and negative pulses in the alternating current are realized by the control unit 111 controlling the on and off of the four switches. Specifically, the control unit 111 controls the first switch S1 and the fourth switch S4 to conduct, and controls the second switch S2 and the third switch S3 to turn off, so that a current in one direction flows through the wire 12; by controlling the first switch S1 and the fourth switch S4 to turn off, and controlling the second switch S2 and the third switch S3 to conduct, so that a current in the other direction flows through the wire 12. Exemplarily, the above four switches are all controllable switch devices, and can be relays or transistors, etc.

[0071] On the basis of the above embodiments, optionally, the power supply module 11 may further include: an ammeter 113, which is arranged at any end of the power supply module 11 and is used to collect the current in the detection loop and provide it to the control unit 111 to achieve precise control of the alternating current.

[0072] To verify whether the magnetic field generated by the electromagnetic base station provided in the embodiment of the present invention meets the measurement requirements, the applicant has carried out actual measurements, and the measurement results are as shown in Figure 3 shown.Figure 3 The magnetic field situation 20 m away from the measurement wire after noise subtraction is provided, and the result proves that the electromagnetic base station can generate a large enough magnetic field within a range of 20 m. Based on the magnetic field generated by the electromagnetic base station and the pipeline positioning system formed by the internal detector, compared with other pipeline positioning methods, it has less environmental impact and lower cost, and can be used for in-service pipeline measurement, with good application prospects.

[0073] An embodiment of the present invention also provides a pipeline positioning system, including the electromagnetic base station provided in any embodiment of the present invention, and having corresponding beneficial effects. Figure 4 It is a schematic structural diagram of the pipeline positioning system provided by the embodiment of the present invention. Refer to Figure 4 , the pipeline positioning system includes: an internal detector 20, a host computer (not shown in the figure), and an electromagnetic base station 10.

[0074] Among them, the internal detector 20 is used to collect magnetic field information in real time along the way when passing through the inside of the pipeline to be measured and store it. The host computer is used to determine the positioning result of the pipeline to be measured according to the reference alternating magnetic field emitted by the electromagnetic base station 10 and the magnetic field information collected by the internal detector 20. Specifically, when the internal detector 20 passes through the inside of the pipeline to be measured, it collects various magnetic fields along the way. The magnetic field information collected by the internal detector 20 may include relevant information obtained by collecting the geomagnetic field, and relevant information obtained by collecting the reference alternating magnetic field, etc. The host computer can extract the relevant information obtained by collecting the reference alternating magnetic field from the magnetic field information collected by the internal detector 20, and then match it with the spatial distribution of the reference alternating magnetic field itself to confirm the position passed by the internal detector 20 and achieve pipeline positioning.

[0075] Exemplarily, the internal detector 20 can be spherical, ellipsoidal, cubic or irregular in shape, preferably a spherical internal detector for moving inside the pipeline to be measured. The spherical internal detector can roll forward in the pipeline to be measured 30. Exemplarily, the rolling frequency of the internal detector 20 can be set different from the frequency of the alternating current to avoid affecting the signal acquisition process of various sensors inside the internal detector 20.

[0076] Among them, at least one electromagnetic base station 10 can be configured in the pipeline positioning system. The number of electromagnetic base stations 10 can be determined according to the pipeline range radiated by a single wire and the total length of the pipeline to be measured 30.

[0077] On the basis of the above embodiments, optionally, the pipeline range radiated by a single wire is limited. For long-distance pipeline positioning. It can be considered that the pipeline to be measured 30 includes multiple sections to be measured S, and at least one electromagnetic base station 10 is correspondingly arranged in the upper area of each section to be measured S. Among them, two or more electromagnetic base stations 10 can be correspondingly arranged in the upper area of one section to be measured S, respectively emitting reference alternating magnetic fields with different distributions to avoid the problem of multiple solutions for the positioning result.

[0078] Among them, multiple electromagnetic base stations 10 of a to-be-detected segment S can be arranged simultaneously, and / or, electromagnetic base stations 10 of adjacent to-be-detected segments S can be arranged simultaneously. In the case of arranging multiple electromagnetic base stations 10 simultaneously, in order to be able to separate the electromagnetic signals corresponding to different electromagnetic base stations 10 in the magnetic field information collected by the in-line detector, different excitation frequencies can be set for different electromagnetic base stations 10. Specifically, it can be set that the difference between the frequencies of the alternating currents in any two electromagnetic base stations 10 corresponding to adjacent two to-be-detected segments S is greater than or equal to a preset frequency difference; and / or, the difference between the frequencies of the alternating currents in any two electromagnetic base stations 10 corresponding to the same to-be-detected segment S is greater than or equal to a preset frequency difference. Exemplarily, the preset frequency difference can be determined according to the resolution of the magnetic field frequency by the magnetometer in the in-line detector, for example, greater than the resolution of the magnetic field frequency by the magnetometer; or, the preset frequency difference can be determined according to the resolution of the magnetic field frequency by the magnetic field information separation algorithm, for example, greater than the possible error range of the VMD algorithm when calculating the signal frequency.

[0079] Based on the above various embodiments, optionally, for any two electromagnetic base stations with different frequencies of alternating current, the frequencies of the alternating currents in the two electromagnetic base stations are not integer multiples. In this way, when using a frequency-based signal decomposition algorithm, such as the VMD algorithm, to separate the magnetic field information, modal aliasing can be avoided, ensuring the reliability of signal separation.

[0080] Based on the above various embodiments, optionally, the in-line detector 20 may include a magnetometer for collecting magnetic field information. When the host computer processes the data after downloading the magnetic field information, it can determine which to-be-detected segment S the data belongs to based on the separated magnetic field data, and then match the magnetic field data with the reference alternating magnetic field of the corresponding to-be-detected segment, and the positioning of the to-be-detected segment can be inversely obtained. Further, the in-line detector may further include an accelerometer for collecting acceleration information, and the acceleration information can assist in confirming when the in-line detector 20 passes through which to-be-detected segment S.

[0081] Based on the above various embodiments, optionally, the pipeline positioning system further includes: a launching device 40 and a receiving device 50. The launching device 40 is arranged at the starting position of the to-be-detected pipeline 30 for launching the in-line detector 20 into the to-be-detected pipeline 30. The receiving device 50 is arranged at the ending position of the to-be-detected pipeline 30 for recovering the in-line detector 20 in the to-be-detected pipeline 30. Based on the launching device 40 and the receiving device 50, the detection process of the in-line detector 20 for ball launching, inspection, and ball receiving can be assisted to be realized.

[0082] Based on the above various embodiments, optionally, the to-be-detected pipeline 30 is a buried pipeline, and the surrounding medium 60 wrapped outside it can be soil.

[0083] Based on the above embodiments, optionally, the laying method of the wire in the electromagnetic base station 10 is determined according to the ground conditions in the area above the pipeline 30 to be measured.

[0084] For example, when the area above the pipeline 30 to be measured is the ground, the wire 12 in the electromagnetic base station 10 can be directly laid on the ground above the pipeline 30 to be measured. It can be understood that since the wire 12 is laid at the detection site, there will inevitably be obstacles at the site. When the wire 12 is laid, there will inevitably be parts that are propped up by the protruding obstacles. This situation still belongs to the category of the wire 12 being directly laid on the ground above the pipeline 30 to be measured. In this case, the wiring of the wire 12 can be flexibly carried out according to the site conditions, as long as the wire 12 is in a stable state with a fixed position on the ground and will not shift during the detection process, resulting in a change in the distribution of the reference alternating magnetic field.

[0085] Or, when there is a water surface above the pipeline 30 to be measured, such as in the case of water accumulation or when passing through a river. The pipeline positioning system can also be configured with: an overhead structure, and the wire 12 in the electromagnetic base station 10 can be arranged above the water surface of the pipeline 30 to be measured through the overhead structure. In this way, the wire 12 can be fixed through the overhead structure to prevent the wire 12 from drifting on the water surface and affecting the distribution of the reference alternating magnetic field.

[0086] Based on the above embodiments, optionally, the pipeline positioning system further includes: a wire positioning device, which is connected to the upper computer. The wire positioning device is used to obtain the laying information of the wire 12 in the electromagnetic base station 10; the upper computer is further used to determine the reference alternating magnetic field emitted by the electromagnetic base station 10 according to the laying information of the wire. Among them, since the wire 12 is laid at the detection site, there will inevitably be obstacles at the site. When the wire 12 is laid, it needs to avoid obstacles and form an irregular shape. In this embodiment, by setting the wire positioning device, the laying situation of the wire can be determined. For example, the coordinates of multiple key points or each point in the wire are measured to form the laying information of the wire 12 and uploaded to the upper computer. The upper computer can calculate the reference alternating magnetic field generated by the measurement wire L1 according to the laying information of the wire 12. In this way, it can be ensured that the distribution of the reference alternating magnetic field obtained by the upper computer conforms to the on-site wiring situation and the positioning accuracy is guaranteed.

[0087] Exemplarily, the wire positioning device can be a satellite positioning device. For a flat wiring situation, such as wiring on a flat ground or on the plane of an overhead structure, a satellite positioning device can be used to measure the positioning of each vertex of the wire to determine the overall wiring situation of the wire.

[0088] Alternatively, the wire positioning device can be a laser positioning device. For non-flat wiring situations, such as wiring on uneven ground or on the three-dimensional structure of an overhead structure, a laser positioning device can be used to measure the coordinate positions of each point of the wire, and based on the Simultaneous Localization and Mapping (SLAM) technology, determine the overall wiring situation of the wire.

[0089] In summary, the embodiment of the present invention proposes a three-dimensional pipeline positioning system based on a low-frequency alternating magnetic field. The system includes an electromagnetic base station, an internal detector, and a host computer. The internal detector is arranged inside the pipeline to be measured and moves forward along the pipeline under the push of gas or fluid inside the pipeline. The electromagnetic base station is arranged above the pipeline to be measured and includes a power supply module and a wire, which are used to generate the reference alternating magnetic field during the positioning process. When the internal detector rolls inside the pipeline, it collects the magnetic field signals generated by the measurement wire, and the host computer uses the VMD algorithm to process the magnetic field information collected by the internal detector, and then inversely calculates the amplitude signal of the magnetic field to obtain accurate pipeline positioning.

[0090] It should be understood that the various forms of processes shown above can be used, and steps can be reordered, added, or deleted. For example, the steps described in the present invention can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. No limitations are imposed herein.

[0091] The above specific embodiments do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. An electromagnetic base station, characterized in that, Applied to a pipeline positioning system; The electromagnetic base station includes: a power supply module and a wire; both ends of the wire are respectively connected to both ends of the power supply module to form a detection loop; at least part of the wire in the detection loop serves as a measurement wire; Wherein, the power supply module is used to provide an alternating current to the wire; the measurement wire is placed in the upper area of the pipeline to be measured, and the measurement wire is used to generate a reference alternating magnetic field required for pipeline positioning when the alternating current flows through it; when the internal detector in the pipeline positioning system passes through the interior of the pipeline to be measured, it collects the reference alternating magnetic field to achieve pipeline positioning.

2. The electromagnetic base station according to claim 1, characterized in that, The power supply module includes: A DC power supply; A current direction adjustment unit connected between the DC power supply and the wire; A control unit connected to the current direction adjustment unit, and is used to control the connection state between the DC power supply and the wire through the current direction adjustment unit to control the current direction provided to the wire.

3. The electromagnetic base station according to claim 2, characterized in that, The current direction adjustment unit includes: A first switch connected between the positive pole of the DC power supply and one end of the power supply module; A second switch connected between the positive pole of the DC power supply and the other end of the power supply module; A third switch connected between the negative pole of the DC power supply and one end of the power supply module; A fourth switch; connected between the negative pole of the DC power supply and the other end of the power supply module; The control unit is respectively connected to the control ends of the first switch, the second switch, the third switch and the fourth switch; And / or, the control unit includes a single-chip microcomputer; And / or, the power supply module further includes: an ammeter, arranged at any end of the power supply module, and is used to collect the current in the detection loop.

4. The electromagnetic base station according to claim 1, characterized in that, The amplitude of the voltage output by the power supply module is less than or equal to the human body safety voltage threshold; The amplitude of the alternating current is greater than or equal to a preset current amplitude; wherein, the preset current amplitude is determined according to the vertical distance between the measurement wire and the pipeline to be measured, and the detection sensitivity of the magnetometer in the internal detector of the pipeline positioning system; The length, material and cross-sectional area of the wire are determined according to the amplitude of the voltage output by the power supply module and the amplitude of the alternating current.

5. The electromagnetic base station according to claim 1, characterized in that, The frequency range of the alternating current is: 1 Hz - 40 Hz; And / or, the frequency of the alternating current is not an integer multiple of the power frequency.

6. The electromagnetic base station according to any one of claims 1-5, characterized in that, Part of the wire in the detection loop serves as a measurement wire, and other wires in the detection loop include an interference section with a current direction opposite to that in the measurement wire; The distance between the measurement wire and the interference section is greater than a first preset distance; wherein, the greater the current amplitude provided by the power supply module to the detection loop, the greater the first preset distance.

7. A pipeline positioning system, characterized in that, Includes: An internal detector, a host computer and an electromagnetic base station according to any one of claims 1 - 6; The internal detector is used to collect magnetic field information when passing through the interior of the pipeline to be measured; The host computer is used to determine the positioning result of the pipeline to be measured according to the reference alternating magnetic field emitted by the electromagnetic base station and the magnetic field information collected by the internal detector.

8. The pipeline positioning system according to claim 7, characterized in that The pipeline to be measured includes a plurality of segments to be measured, and at least one of the electromagnetic base stations is correspondingly arranged in the area above each segment to be measured; The difference between the frequencies of the alternating currents in any two of the electromagnetic base stations respectively corresponding to two adjacent segments to be measured is greater than or equal to a preset frequency difference; and / or, the difference between the frequencies of the alternating currents in any two of the electromagnetic base stations corresponding to the same segment to be measured is greater than or equal to a preset frequency difference.

9. The pipeline positioning system according to claim 8, wherein For any two of the electromagnetic base stations with different frequencies of the alternating current, the frequencies of the alternating currents in the two electromagnetic base stations are not integer multiples of each other.

10. The pipeline positioning system according to claim 7, characterized in that, The wire in the electromagnetic base station is laid on the ground above the pipeline to be measured; Alternatively, the pipeline positioning system further includes: an overhead structure, and the wire in the electromagnetic base station is arranged on the water surface above the pipeline to be measured through the overhead structure.

11. The pipeline positioning system according to claim 7 or 10, characterized in that, It further includes: A wire positioning device, connected to the host computer; the wire positioning device is used to obtain the layout information of the wire in the electromagnetic base station; the host computer is further used to determine the reference alternating magnetic field emitted by the electromagnetic base station according to the layout information of the wire.

12. The pipeline positioning system according to claim 7, wherein, It further includes: A feeding device, arranged at the starting position of the pipeline to be measured, for feeding the internal detector into the pipeline to be measured; A receiving device, arranged at the ending position of the pipeline to be measured, for recovering the internal detector in the pipeline to be measured.

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