CN107817531B - Pipeline instrument receiver coil structure, signal processing method and pipeline instrument receiver - Google Patents

Abstract

The invention belongs to the technical field of power cables, and discloses a coil structure and a signal processing method of a pipeline instrument receiver, and a pipeline instrument receiver. The receiver collects magnetic field signals of buried cables through a coil, and combines analog signal conditioning and digital signal processing. method to calculate the position information of the cable. The first horizontal coil detects the magnetic field signal of the buried cable in the horizontal direction, and the combination with the second horizontal coil is used to measure the buried depth and current of the buried cable; the vertical coil detects the magnetic field signal of the buried cable in the vertical direction, The combination with the first horizontal coil is used to detect the left and right positions of the buried cable; the combination of the third horizontal coil and the second horizontal coil is used to measure the angle between the receiver and the buried cable to realize the compass function. The pipeline instrument receiver of the invention has high reliability, compact and reasonable coil structure, complete detection functions, low cost, good anti-interference, and high detection precision and sensitivity.

Description

Coil structure and signal processing method of pipeline instrument receiver, pipeline instrument receiver

technical field

The invention belongs to the technical field of power cables, and in particular relates to a coil structure and a signal processing method of a pipeline instrument receiver, and a pipeline instrument receiver.

Background technique

In recent years, with the rapid development of domestic power grids, buried cables have been widely used in order to reduce overhead lines occupying too much space resources. Considering that the transformation of the power grid and the relocation of the cables may make the original drawings and data unable to correctly reflect the laying path of the underground cables, for the underground cables, if the location information is not clear enough, it is very difficult to find, which not only wastes a lot of manpower, material resources and time, but also will cause incalculable losses. The domestic research on buried cable path detection started late, but the development speed is relatively fast. At present, there are many scientific research units, colleges and universities and related enterprises specializing in the research of buried cable path detection. Great breakthroughs have been made in the above, which has improved our country's ability to detect buried cable paths as a whole. At present, the detection of buried cables in China is mainly based on the detection principle of the electromagnetic method. The magnetic field around the buried cable is detected by the combination of multiple sets of coils, and the position of the cable is determined by judging the strength of the magnetic field signal. This method is particularly important for the structural design of the coil. Traditional receivers usually use one or two sets of coils to detect buried cables. This method can perform simple and effective measurement, but the detection accuracy is not high, the anti-interference is poor, the function is single, and the overall detection efficiency is low. Among them, an intelligent cable path detector is proposed in the paper titled "Research and Design of Intelligent Cable Path Detector". The coil structure of the cable path detector consists of 8 sets of detection coils. The specific structure is: the upper part is a A set of horizontal coils and a set of vertical coils, a set of vertical coils in the middle and four sets of horizontal coils in four different directions, front, rear, left, right, and left, and a set of horizontal coils at the bottom; The horizontal coil is used to measure the depth and current of the buried cable. Four sets of horizontal coils in the front, rear, left and right directions realize the compass function by comparing the magnitude of the induced voltage of the coil, because the deflection direction of the receiver relative to the cable is only judged by comparing the magnitude of the electromotive force. Therefore, the compass function can only realize the 45-degree angle indication in four directions, front, rear, left, right and each direction, and cannot realize the indication of any angle. The compass function is not very perfect. The Chinese patent document No. 201320110499.2 discloses a high-precision underground cable detector. The receiving antenna module of the detector includes two sets of horizontal coils and one set of vertical coils. The two sets of horizontal coils are located at the top and bottom of the bracket. The middle is a vertical coil, and the specific structure is an "I"-shaped coil structure; the middle vertical coil and the lower horizontal coil are used to detect the left and right positions of the buried cable, and the upper and lower sets of horizontal coils are used to measure the buried depth and current. Although the patented coil structure design is relatively simple, it cannot realize the compass indication function, the detection function is incomplete, and measures to suppress external interference are not taken, and the overall efficiency is not high.

To sum up, the problems existing in the prior art are: the compass indication function cannot be realized, the detection function is incomplete, and measures to suppress external interference are not taken, and the overall efficiency is not high.

SUMMARY OF THE INVENTION

Aiming at the problems existing in the prior art, the present invention provides a pipeline instrument receiver coil structure and signal processing method, and a pipeline instrument receiver.

The present invention is implemented in this way, a signal processing method of the pipeline instrument receiver coil structure, the signal processing method of the pipeline instrument receiver coil structure includes:

Conditioning of analog signals to adjust and process the induced voltage signal generated in the coil;

The conversion of analog-to-digital signal is used to convert the analog signal output by the signal conditioning circuit into a digital signal;

Digital signal processing is used to restore the energy spectrum of the received frequency signal and calculate the position information of the cable.

The signal processing method further includes: the receiver collects the magnetic field signal of the buried cable through program switching and selecting different coil combinations, and the magnetic field signal is biased, filtered and amplified through the coil circuit board and transmitted to the receiver core board, Once again, the signal conditioning circuit performs differential amplification, low-pass filtering, and reverse amplification processing and then sends it to the A/D converter. The A/D converter sends the converted digital signal to the DSP for digital signal processing. Based on the characteristics of the new coil structure And the derivation and calculation method of its theoretical formula, finally get the position of the buried cable, and display it in real time through the LCD screen.

The derivation and calculation method based on the characteristics of the new coil structure and its theoretical formula includes: judgment of the left and right positions of the cable, calculation of the buried depth of the cable and the magnitude of the current, and calculation of the angle between the receiver and the cable;

The judgment of the left and right position of the cable is realized by the combination of the first horizontal coil and the vertical coil; when there is a current I in the cable, the magnetic field strengths received by the first horizontal coil and the vertical coil are respectively:

Among them, μ ₀ is the magnetic permeability of the medium in vacuum, μ ₀ =4π×10 ^-7 H/m, h is the vertical distance from the first horizontal coil and the vertical coil to the cable, and x is the distance between the first horizontal coil and the vertical coil to the cable the horizontal distance of the cable;

The calculation of cable buried depth and current size is realized by the combination of the first horizontal coil and the second horizontal coil; when the receiver is located directly above the buried cable, the induced electromotive force generated in the first horizontal coil and the second horizontal coil They are:

Among them, I is the current intensity in the cable, h is the vertical distance from the first horizontal coil to the cable, d is the vertical distance between the first horizontal coil and the second horizontal coil, and S ₁ and S ₃ are the first horizontal coil, respectively and the cross-sectional area _of the second horizontal coil, S1 and S3 are equal in size, ω is the angular frequency _of the current signal in the cable; when the first horizontal coil is in contact with the ground, h is the buried depth of the cable; the buried depth of the cable h and The current magnitude I is:

The calculation of the angle between the receiver and the cable is realized by the combination of the second horizontal coil and the third horizontal coil; when there is a current I in the cable, the induced electromotive force generated in the second horizontal coil and the third horizontal coil are respectively :

Among them, N3 and _N4 are the turns of the second horizontal coil and the _third horizontal coil, respectively, S3 and S4 are the cross _- sectional areas of the second horizontal coil and the third horizontal coil, respectively, h is the second horizontal coil and the third horizontal coil _. The vertical distance from the three horizontal coils to the cable, x is the horizontal distance from the second horizontal coil and the third horizontal coil to the cable, θ ₃ and θ ₄ are the included angles between the second horizontal coil and the third horizontal coil and the cable respectively;

Since the installation positions of the second horizontal coil and the third horizontal coil are vertical, the relationship between θ ₃ and θ ₄ is:

θ ₃ +θ ₄ =90°;

Then, from the above formula we get:

The number of turns N3 of the second horizontal coil and the number of turns N4 of the _third horizontal coil ₄ are equal, and the cross-sectional area S3 of the second horizontal coil and the cross _- sectional area S4 of the _third horizontal coil are equal, then the clamp between the receiver and the cable The angle _θ3 is:

Another object of the present invention is to provide a pipeline instrument receiver coil structure, and the pipeline instrument receiver coil structure includes:

The first horizontal coil is used to detect the magnetic field signal of the buried cable in the horizontal direction, and the combination with the second horizontal coil is used to measure the buried depth and current of the buried cable;

The vertical coil is used to detect the magnetic field signal of the buried cable in the vertical direction, and the combination with the first horizontal coil is used to detect the left and right positions of the buried cable;

The third horizontal coil, the installation position is perpendicular to the second horizontal coil, and the combination with the second horizontal coil is used to measure the angle between the receiver and the buried cable, so as to realize the compass function;

Brackets for mounting and fixing four sets of coils in specific positions.

Further, the first horizontal coil and the vertical coil are located at the bottom of the bracket, and the second horizontal coil and the third horizontal coil are located at the top of the bracket; the combination of the first horizontal coil and the vertical coil is used to detect the left and right positions of the buried cable; The combination of the coil and the second horizontal coil is used to measure the depth and current of the buried cable; the combination of the second horizontal coil and the third horizontal coil is used to realize the compass indication function; the bracket is used to fix and install the four sets of receiving coils in a specific The position of the coil circuit board is used for bias adjustment, filtering and amplification of the magnetic field signal collected by the coil, and the receiver core board is used to realize the switching of different coil combinations, the conditioning of the coil signals, and the A/D signal. Conversion, digital signal processing, human-computer interaction functions.

Further, the coil circuit board includes:

Coil welding hole for welding receiver coil;

Bias adjustment circuit for providing bias voltage;

The clamp protection circuit is used to limit the voltage of the input signal and acts as a protection circuit;

Filter and amplify circuit, used to filter out the interference of out-of-band signals and amplify the input signal;

The connector is used to connect the receiver core board.

Further, the core control board of the receiver includes:

SDRAM module, FLASH module, crystal oscillator circuit, reset circuit, power supply module, JTAG configuration module, A/D conversion circuit, signal conditioning circuit, multi-channel selection circuit, audio power amplifier module, liquid crystal display module, and key module are all electrically connected to the DSP module. Connection; the receiver controls the multi-channel selection switch through the program, and selects the signal conditioning circuit corresponding to different coils. The signal conditioning circuit adjusts and processes the magnetic field signals collected by each group of coils and outputs it to the audio power amplifier circuit and A/D converter. , the audio power amplifier circuit converts the analog electrical signal into a sound signal, and judges the strength of the received magnetic field signal by the size of the speaker's sound; the A/D converter transmits the converted digital signal to the DSP for digital signal processing. The FIR digital filtering algorithm and the theoretical formula based on the coil structure are used to calculate the position information of the buried cable, which can be displayed in real time through the LCD screen to finally determine the position of the cable.

The SDRAM module is used to temporarily store the operation data in the CPU and the data exchanged with FLASH;

FLASH module, used to store the system program of the receiver;

Crystal oscillator circuit, used to provide basic clock signal to CPU and other circuit modules;

The reset circuit is used to ensure the safe and reliable operation of the receiver core board circuit;

Power supply module for powering the entire receiver system;

JTAG configuration circuit, used for emulation and debugging of receiver core board;

A/D conversion circuit is used to convert the analog voltage signal collected by the coil into a digital signal, which is convenient for DSP to perform digital signal processing;

A signal conditioning circuit to further adjust and process the magnetic field signal collected by the coil;

Multi-channel selection circuit for selecting different coil combinations;

The audio power amplifier module is used to assist in prompting the strength of the magnetic field signal detected by the receiver;

The liquid crystal display module is used to display the cable path indication, received signal strength, received frequency, compass indication, battery power, and menu information of the human-computer interaction interface;

The button module is used to operate the human-computer interface.

Further, the signal conditioning circuit includes:

The differential comparison circuit is used to differentially amplify and output the input signal at both ends of the coil;

The second-order low-pass filter circuit is used to filter out high-frequency interference signals outside the passband;

The reverse proportional operation circuit is used to provide a stable reverse output signal and improve the load capacity.

Another object of the present invention is to provide a coil structure of the pipeline instrument receiver;

The coil structure consists of four sets of coils. The first horizontal coil and the vertical coil are installed at the bottom of the bracket, the second horizontal coil and the third horizontal coil are installed at the top of the bracket, and are packaged in the receiver through a cylinder of 600mm×6mm×120mm. The overall shape of the receiver is light and easy to carry; the different combinations of four groups of receiving coils can realize the detection of the magnetic field signal strength, the judgment of the left and right position of the cable, the measurement of the cable depth and the size of the current, and the compass indication function; The number is small, the structure is compact and reasonable, and the detection functions are complete. It only needs less signal processing circuits, which is easy to implement. Combined with signal differential technology and digital transmission, the common mode interference is effectively suppressed and the anti-interference ability of the system is improved. After signal amplification The distortion is small, and the detection effect is good in the weak magnetic field environment; the core board of the receiver adopts a 32-bit DSP processor, which enhances the processing speed and computing power of the receiver system, and improves the detection speed of the receiver. The response time is about 100ms; and it is equipped with a 24-bit AD converter, which has higher conversion accuracy and sampling rate, which improves the measurement accuracy of the receiver. The actual measurement error is about 2cm-5cm, which effectively improves the Efficiency of buried cable path detection.

Description of drawings

1 is a schematic structural diagram of a pipeline instrument receiver coil provided by an embodiment of the present invention;

FIG. 2 is a schematic diagram of an overall design of a receiver core board card provided by an embodiment of the present invention;

3 is a schematic diagram of a method for judging the left and right position of a cable according to an embodiment of the present invention;

4 is a schematic diagram of a method for calculating cable buried depth and current magnitude provided by an embodiment of the present invention;

5 is a schematic diagram of a method for calculating an angle between a receiver and a cable provided by an embodiment of the present invention;

6 is a schematic diagram of a hardware function structure of a receiver core board card provided by an embodiment of the present invention;

In the figure: 1. The first horizontal coil; 2. The vertical coil; 3. The second horizontal coil; 4. The third horizontal coil; 5. The bracket; 6. The coil circuit board; 7. The receiver core board.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

The invention has higher detection accuracy and speed, and also has a better detection effect in a weak magnetic field environment, and effectively improves the detection efficiency of the buried cable path.

The application principle of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 1 , the coil structure of the pipeline instrument receiver provided by the embodiment of the present invention includes:

First horizontal coil 1 , vertical coil 2 , second horizontal coil 3 , third horizontal coil 4 , bracket 5 , coil circuit board 6 , receiver core board 7 .

The first horizontal coil 1 is used to detect the magnetic field signal of the buried cable in the horizontal direction, and the combination with the second horizontal coil 3 is used to measure the buried depth and current magnitude of the buried cable.

The vertical coil 2 is used to detect the magnetic field signal of the buried cable in the vertical direction, and the combination with the first horizontal coil 1 is used to detect the left and right positions of the buried cable.

The third horizontal coil 4, the installation position is perpendicular to the second horizontal coil 3, and the combination with the second horizontal coil 3 is used to measure the angle between the receiver and the buried cable, so as to realize the compass function.

The bracket 5 is used to install and fix the four sets of coils in a specific position.

The first horizontal coil 1 and the vertical coil 2 are located at the bottom of the bracket, and the second horizontal coil 3 and the third horizontal coil 4 are located at the top of the bracket; the combination of the first horizontal coil 1 and the vertical coil 2 is used to detect the left and right positions of the buried cable; The combination of a horizontal coil 1 and a second horizontal coil 3 is used to measure the depth and current of the buried cable; the combination of the second horizontal coil 3 and the third horizontal coil 4 is used to realize the compass indication function; the bracket 5 is used to connect the four groups The receiving coil is fixed and installed in a specific position; the coil circuit board 6 is used to perform preliminary processing such as bias adjustment, filtering, and amplification on the magnetic field signal collected by the coil, and the receiver core board 7 is used to realize the switching of different coil combinations. , Coil signal conditioning, A/D signal conversion, digital signal processing, human-computer interaction functions, etc.

In a preferred embodiment of the present invention: the four groups of coils of the coil structure are respectively fixed at specific positions by the receiver coil bracket, and the pipeline instrument receiver detects the magnetic field signal of the buried cable through program switching and selection of different coil combinations, as shown in the figure As shown in 2, the magnetic field signal collected by the coil is firstly processed by the coil circuit board for bias adjustment, filtering, amplification, etc., and then transmitted to the receiver core board, and then differential amplification, low-pass filtering, and reverse amplification are performed by the signal conditioning circuit. After processing, it is sent to the A/D converter. The A/D converter sends the converted digital signal to the DSP for digital signal processing. Based on the characteristics of the new coil structure and the derivation and calculation of its theoretical formula, the buried cable is finally obtained. position and display it in real time on the LCD screen.

In a preferred embodiment of the present invention: the derivation and calculation method of the characteristics of the novel coil structure and its theoretical formula include: judgment of the left and right position of the cable, calculation of the buried depth of the cable and the magnitude of the current, and calculation of the angle between the receiver and the cable;

The judgment of the left and right position of the cable is realized by the combination of the first horizontal coil 1 and the vertical coil 2, as shown in Figure 3; when there is a current I in the cable, the magnetic field received by the first horizontal coil 1 and the vertical coil 2 The strengths are:

Among them, μ ₀ is the magnetic permeability of the medium in vacuum (μ ₀ =4π×10 ⁻⁷ H/m), h is the vertical distance from the first horizontal coil 1 and the vertical coil 2 to the cable, and x is the first horizontal coil 1 and the horizontal distance from the vertical coil 2 to the cable;

When the vertical coil 2 is located on the left side of the cable, the direction of H ₂ is vertically upward; when the vertical coil 2 is located on the right side of the cable, the direction of H ₂ is vertically downward; and the direction of H ₁ is always horizontal to the right, By judging the sign of H ₁ ×H ₂ , it can be determined whether the receiver is located on the left or right side of the cable;

The calculation of cable burial depth and current is realized by the combination of the first horizontal coil 1 and the second horizontal coil 3, as shown in Figure 4; when the receiver is located directly above the buried cable, the first horizontal coil 1 and the induced electromotive force generated in the second horizontal coil 3 are:

Among them, I is the current intensity in the cable, h is the vertical distance from the first horizontal coil 1 to the cable, d is the vertical distance between the first horizontal coil ₁ and the second horizontal coil ₃ , and S1 and S3 are the The cross-sectional area of a horizontal coil ₁ and the second coil ₃ , S1 and S3 are equal in size, ω is the angular frequency of the current signal in the cable; when the first horizontal coil 1 is in contact with the ground, h is the buried depth of the cable; The buried depth h and current magnitude I are:

The calculation of the angle between the receiver and the cable is realized by the combination of the second horizontal coil 3 and the third horizontal coil 4, as shown in Figure 5; when the current I flows through the cable, the second horizontal coil 3 and the third horizontal coil The induced electromotive forces generated in the horizontal coil 4 are:

Among them, N3 and _N4 are the number of turns of the second coil ₃ and the third coil ₄ , respectively, S3 and S4 are the cross-sectional areas of the second horizontal coil ₃ and the third horizontal coil 4, respectively, and h is the second horizontal coil 3. and the vertical distance from the third horizontal coil 4 to the cable, x is the horizontal distance from the second horizontal coil 3 and the third horizontal coil 4 to the cable, θ ₃ and θ ₄ are the second horizontal coil 3 and the third horizontal coil 4 and the the angle between the cables;

Since the installation positions of the second horizontal coil 3 and the third horizontal coil 4 are vertical, the relationship between θ ₃ and θ ₄ is:

θ ₃ +θ ₄ =90° (5)

Then, from the above formula we get:

In the present invention, the number of turns N3 of the second horizontal coil 3 is equal to the number of turns _N4 of the _third horizontal coil 4, and the cross-sectional area S3 of the second horizontal coil ₃ and the cross-sectional area S4 of the third horizontal coil ₄ are equal, then _The included angle θ3 between the receiver and the cable is:

As shown in FIG. 6, the hardware design of the receiver core board 7 of the present invention includes: DSP module, SDRAM module, FLASH module, crystal oscillator circuit, reset circuit, power supply module, JTAG configuration module, A/D conversion circuit, signal conditioning Circuit, multi-channel selection circuit, audio power amplifier module, liquid crystal display module, button module.

SDRAM module, FLASH module, crystal oscillator circuit, reset circuit, power supply module, JTAG configuration module, A/D conversion circuit, signal conditioning circuit, multi-channel selection circuit, audio power amplifier module, liquid crystal display module, and key module are all electrically connected to the DSP module. connect.

The SDRAM module is used to temporarily store the operation data in the CPU and the data exchanged with the FLASH.

The FLASH module is used to store the system program of the receiver.

The crystal oscillator circuit is used to provide the basic clock signal to the CPU and other circuit modules.

The reset circuit is used to ensure the safe and reliable operation of the receiver core board circuit.

Power supply module for powering the entire receiver system.

The JTAG configuration circuit is used for emulation and debugging of the receiver core board.

The A/D conversion circuit is used to convert the analog voltage signal collected by the coil into a digital signal, which is convenient for DSP to perform digital signal processing.

A signal conditioning circuit for further conditioning and processing the magnetic field signal acquired by the coil.

Multiple channel selection circuit for selecting different coil combinations.

The audio power amplifier module is used to assist in prompting the strength of the magnetic field signal detected by the receiver.

The liquid crystal display module is used to display the cable path indication, received signal strength, received frequency, compass indication, battery level, menu and other information of the human-computer interaction interface.

The button module is used to operate the human-computer interface.

In the hardware platform of the receiver core board card of the present invention, the CPU uses the ADSP chip of the dual Blackfin cores of ADI Corporation of the United States, and each core includes two multiply/accumulate accumulators (MAC), two 40-bit arithmetic logic units ( ALU), 4 video ALUs and a 40-bit shifter, can perform complex control and signal processing tasks while maintaining extremely high data throughput. The above hardware conditions help to quickly realize the relevant algorithms and improve the running speed of the system.

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (6)

1. A signal processing method of a pipeline instrument receiver coil structure is characterized by comprising the following steps:

the analog signal conditioning is used for adjusting and processing the induced voltage signal generated in the coil;

the conversion of the analog-to-digital signal is used for converting the analog signal into a digital signal;

the digital signal processing is used for restoring the energy spectrum of the received frequency signal and calculating the position information of the cable; the signal processing method further includes: the receiver acquires magnetic field signals of the buried cable through program switching and different coil combinations, the magnetic field signals are subjected to bias adjustment, filtering and amplification through a coil circuit board card and then transmitted to a receiver core board card, the magnetic field signals are subjected to differential amplification, low-pass filtering and reverse amplification through a signal conditioning circuit and then transmitted to an A/D converter, the A/D converter sends the converted digital signals to a DSP (digital signal processor) for digital signal processing, and finally position information of the buried cable is obtained and displayed in real time through a liquid crystal screen based on the characteristics of a novel coil structure and a derivation and calculation method of a theoretical formula of the novel coil structure;

the derivation and calculation method based on the characteristics of the novel coil structure and the theoretical formula thereof comprises the following steps: judging the left and right positions of the cable, calculating the buried depth and the current of the cable, and calculating the included angle between the receiver and the cable;

the judgment of the left and right positions of the cable is realized by the combination of the first horizontal coil and the vertical coil; when the cable is electrified with current I, the magnetic field intensity received by the first horizontal coil and the vertical coil is respectively as follows:

wherein, mu₀Is the permeability of the medium in vacuum, mu₀＝4π×10^-7H/m, H is the vertical distance from the first horizontal coil and the vertical coil to the cable, and x is the horizontal distance from the first horizontal coil and the vertical coil to the cable;

the calculation of the buried depth of the cable and the magnitude of the current is realized by the combination of the first horizontal coil and the second horizontal coil; when the receiver is positioned right above the buried cable, the induced electromotive forces generated in the first horizontal coil and the second horizontal coil are respectively:

wherein I is the current intensity in the cable, h is the vertical distance from the first horizontal coil to the cable, d is the vertical distance between the first horizontal coil and the second horizontal coil, S₁And S₃The sectional areas, S, of the first horizontal coil and the second horizontal coil, respectively₁And S₃The sizes are equal, and omega is the angular frequency of a current signal in the cable; when the first horizontal coil is in contact with the ground, h is the buried depth of the cable; the buried depth h and the current I of the cable are as follows:

the calculation of the included angle between the receiver and the cable is realized by the combination of the second horizontal coil and the third horizontal coil; when the cable is electrified with current I, the induced electromotive forces generated in the second horizontal coil and the third horizontal coil are respectively as follows:

wherein N is₃And N₄Number of turns, S, of the second horizontal coil and the third horizontal coil, respectively₃And S₄Sectional areas of the second horizontal coil and the third horizontal coil, respectively, h is a vertical distance from the second horizontal coil and the third horizontal coil to the cable, x is a horizontal distance from the second horizontal coil and the third horizontal coil to the cable, and theta₃And theta₄The included angles between the second horizontal coil and the cable and the included angles between the third horizontal coil and the cable are respectively included;

since the mounting positions of the second horizontal coil and the third horizontal coil are perpendicular, θ₃And theta₄The relationship of (1) is:

θ₃+θ₄＝90°；

then, it is obtained from the above equation:

number of turns N of second horizontal coil₃And the number of turns N of the third horizontal coil₄Equal, second horizontal coil cross-sectional area S₃And cross-sectional area S of the third horizontal coil₄Equal, the angle theta between the receiver and the cable₃Comprises the following steps:

the pipeline instrument receiver coil structure comprises:

the first horizontal coil is used for detecting a magnetic field signal of the buried cable in the horizontal direction, and the combination of the first horizontal coil and the second horizontal coil is used for measuring the buried depth and the current magnitude of the buried cable;

the vertical coil is used for detecting a magnetic field signal of the buried cable in the vertical direction, and the combination of the vertical coil and the first horizontal coil is used for detecting the left and right positions of the buried cable;

the third horizontal coil is perpendicular to the second horizontal coil in installation position, and the combination of the third horizontal coil and the second horizontal coil is used for measuring the included angle between the receiver and the buried cable so as to realize the compass function;

and the bracket is used for mounting and fixing the four groups of coils at a specific position.

2. The signal processing method of a pipeline instrument receiver coil structure of claim 1, wherein the first horizontal coil and the vertical coil are located at the bottom of the support, and the second horizontal coil and the third horizontal coil are located at the top of the support; the combination of the first horizontal coil and the vertical coil is used for detecting the left and right positions of the buried cable; the combination of the first horizontal coil and the second horizontal coil is used for measuring the depth and the current magnitude of the buried cable; the combination of the second horizontal coil and the third horizontal coil is used for realizing a compass indication function; the bracket is used for fixing and installing the four groups of receiving coils at a specific position; the coil circuit board card is used for carrying out bias adjustment, filtering and amplification preliminary processing on the magnetic field signals acquired by the coils, and the receiver core board card is used for realizing the functions of switching different coil combinations, conditioning the coil signals, converting A/D signals, processing digital signals and carrying out human-computer interaction.

3. The signal processing method of the pipeline instrument receiver coil structure as claimed in claim 2, wherein the coil circuit board card comprises:

the coil welding hole is used for welding the receiver coil;

a bias adjustment circuit for providing a bias voltage;

the clamp protection circuit is used for limiting the voltage of an input signal and playing a role of a protection circuit;

the filtering and amplifying circuit is used for filtering out the interference of the out-of-band signal and amplifying the input signal;

and the connecting seat is used for connecting the core board card of the receiver.

4. The signal processing method of the coil structure of the pipeline instrument receiver as claimed in claim 2, wherein the receiver core control board comprises:

the SDRAM module, the FLASH module, the crystal oscillator circuit, the reset circuit, the power supply module, the JTAG configuration module, the A/D conversion circuit, the signal conditioning circuit, the multi-channel selection circuit, the audio power amplifier module, the liquid crystal display module and the key module are all electrically connected with the DSP module; the receiver controls the multi-channel selection switch through a program, selects the signal conditioning circuits corresponding to different coils, the signal conditioning circuits adjust and process the magnetic field signals collected by each group of coils and then output the magnetic field signals to the audio power amplification circuit and the A/D converter, the audio power amplification circuit converts the analog electric signals into sound signals, and the strength of the received magnetic field signals is judged according to the sound of the loudspeaker; the A/D converter transmits the converted digital signals to a DSP for digital signal processing, the position information of the buried cable is calculated through an improved FIR digital filtering algorithm and theoretical formula derivation based on a coil structure, real-time display is carried out through a liquid crystal display, and the position of the cable is finally determined;

the SDRAM module is used for temporarily storing operation data in the CPU and data exchanged with the FLASH;

the FLASH module is used for storing a system program of the receiver;

the crystal oscillator circuit is used for providing basic clock signals for the CPU and other circuit modules;

the reset circuit is used for ensuring the safe and reliable work of the receiver core board card circuit;

the power supply module is used for supplying power to the whole receiver system;

the JTAG configuration circuit is used for simulation debugging of the core board card of the receiver;

the A/D conversion circuit is used for converting the analog voltage signal acquired by the coil into a digital signal, so that the DSP can conveniently process the digital signal;

the signal conditioning circuit is used for further adjusting and processing the magnetic field signal acquired by the coil;

a multipath channel selection circuit for selecting different coil combinations;

the audio power amplifier module is used for assisting in prompting the strength of the magnetic field signal detected by the receiver;

the liquid crystal display module is used for displaying cable path indication, received signal strength, received frequency, compass indication, battery electric quantity and menu information of the human-computer interaction interface;

and the key module is used for operating the human-computer interaction interface.

5. The method of signal processing for a pipeline instrument receiver coil structure of claim 4, wherein the signal conditioning circuit comprises:

the differential comparison circuit is used for carrying out differential amplification output on input signals at two ends of the coil;

the second-order low-pass filter circuit is used for filtering high-frequency interference signals outside a passband;

and the inverse proportion operation circuit is used for providing a stable inverse output signal and improving the load capacity.

6. A pipeline tool receiver using the signal processing method of the pipeline tool receiver coil structure of claim 1.

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