A primary field compensation time-frequency electromagnetic detection device and method

Abstract

The present application discloses a primary field compensation time-frequency electromagnetic detection device and method, the device comprising: a transmitting coil, a compensation coil and a receiving sensor, wherein the transmitting coil and the compensation coil are regular shapes, and the transmitting coil and the compensation coil are of the same shape; the transmitting coil surrounds the compensation coil, and the compensation coil surrounds the receiving sensor; the transmitting coil and the compensation coil are connected in reverse series. A resistor R is connected in parallel at both ends of the compensation coil. The present application solves the problems existing in the two electromagnetic detection methods of time domain and frequency domain in the prior art, thereby overcoming the disadvantage that the primary field in the time domain is doped in the early moments of the secondary field response curve, causing the shallow information to be "annihilated" and the shallow detection "blind area" to be generated, and using the advantages of the frequency domain electromagnetic detection with strong anti-interference ability and large detection depth to solve the geological problems of shallow and ultra-shallow electromagnetic detection.

Description

Technical Field

[0001] The present application relates to the field of electromagnetic detection, and in particular, to a primary field compensation time-frequency electromagnetic detection device and method. Background Art

[0002] With the progress of engineering construction and resource exploration, some shallow and ultra-shallow geological problems have also been exposed. In order to solve these geological problems, some new shallow geophysical exploration methods have been developed in recent years to solve these problems. The electromagnetic detection method is one of the important methods.

[0003] The electrical properties of various media and objects (including resistivity, electrochemical properties, dielectric properties, magnetic permeability, etc.) are different, which can form natural and artificial electromagnetic fields with certain rules. Detecting and studying the distribution of natural or artificial electromagnetic fields can achieve the purpose of studying geological structures, finding mineral deposits, and detecting underground objects. Shallow and ultra-shallow geophysical exploration based on electromagnetic detection can effectively solve many engineering problems that are difficult to solve with other methods, and it is fast, convenient, and economical. Its methods, technologies, and application fields are constantly expanding.

[0004] From the perspective of data processing, the technical means of electromagnetic detection are mainly divided into two types: time domain and frequency domain. Time domain electromagnetic detection is to emit a current of a certain energy (generally called the primary field) to the target medium, generate excitation to the target medium, and then quickly shut down the current source, sense and record the excitation response (generally called the secondary field) curve of the target medium through electric or magnetic sensors, analyze the response curve characteristics of different media, and then characterize the electrical characteristics of the target medium. The advantage of time domain electromagnetic detection is that the secondary field response curve is intuitive and has high resolution. After overcoming the influence of the primary field, it can detect ultra-shallow targets, greatly reducing or even eliminating the detection "blind area"; the disadvantage is that due to the characteristics of electronic devices and the capacitance and inductance characteristics of the transmitting sensor itself, the transmitting current cannot meet the theoretical fast shutdown requirements, resulting in the primary field being doped in the early moments of the secondary field response curve, causing the shallow information to be "annihilated" and resulting in a shallow detection "blind area". In addition, due to the large dynamic range and wide bandwidth of the secondary field, it is impossible to perform unified signal amplification and filtering, the late signal is weak, the signal-to-noise ratio is low, the data quality is poor, and the detection depth is shallow.

[0005] Frequency domain electromagnetic detection is to emit a single-frequency or multi-frequency bipolar current waveform of a certain energy to the target medium to generate excitation to the target medium, sense and analyze the excitation response spectrum characteristics of the target medium through electric or magnetic sensors, analyze the response characteristics of different media to different frequencies, and then characterize the electrical characteristics of the target medium. The advantage of frequency domain electromagnetic detection is that it directly analyzes the medium excitation response spectrum superimposed on the primary field, and the signal has a small dynamic range and narrow frequency band, which is convenient for unified signal amplification and filtering, strong anti-interference ability and large detection depth; the disadvantage is that due to the limited number of excitation frequencies for the emitted single-frequency or multi-frequency bipolar current waveform, the spectrum density is insufficient and the longitudinal resolution is insufficient. Summary of the invention

[0006] The embodiments of the present application provide a primary field compensation time-frequency electromagnetic detection device and method to at least solve the problems existing in the time domain and frequency domain electromagnetic detection methods in the prior art.

[0007] According to one aspect of the present application, a primary field compensation time-frequency electromagnetic detection device is provided, comprising: a transmitting coil, a compensating coil and a receiving sensor, wherein the shapes of the transmitting coil and the compensating coil are regular shapes, and the shapes of the transmitting coil and the compensating coil are the same; the transmitting coil surrounds the compensating coil, and the compensating coil surrounds the receiving sensor; the transmitting coil and the compensating coil are reversely connected in series, and the two ends of the reverse series connection are respectively connected to the positive output wiring port and the negative output wiring port of the transmitting system, and the two ends of the receiving sensor are connected to the signal input terminal of the receiving system; a resistor R is connected in parallel at both ends of the compensating coil.

[0008] Furthermore, the resistance value of the resistor R is configured such that under a predetermined environment, when the transmitting system transmits a current signal to the transmitting coil and the compensation coil, the resistance value of the resistor R can make the receiving signal of the receiving system infinitely close to zero.

[0009] Further, the predetermined environment is a shielded environment with relatively no interference and no magnetic field, and the device is suspended in the device.

[0010] Further, the resistance value of the resistor R is configured to enable the magnetic induction intensities of the transmitting coil and the compensation coil to be the same, and the directions of the magnetic induction intensities to be opposite.

[0011] Furthermore, the shape of the transmitting coil and the compensation coil is one of the following: circular, rectangular, and regular polygonal.

[0012] Furthermore, the receiving sensor is one of the following: a coil, a flux gate, and a magnetic bar.

[0013] Furthermore, the waveform emitted by the emission system is a mixed waveform of a unipolar pulse waveform and a bipolar pulse waveform.

[0014] Furthermore, the period of the mixed wave generated by the transmitting system is T, and in the period T, the signal level is 0 for part of the time.

[0015] Furthermore, the bipolar pulse waveform includes at least one of the following: a single frequency wave, a n Pseudo-random signal waveform, m-sequence waveform.

[0016] According to another aspect of the present application, a primary field compensation time-frequency electromagnetic detection method is also provided, characterized in that detection is performed using the above-mentioned device, including: the transmitting system generates a waveform, wherein the waveform is transmitted by the transmitting coil and the compensation coil; the waveform is received by the receiving sensor; and the receiving system performs electromagnetic detection based on the waveform received by the receiving sensor.

[0017] In the embodiment of the present application, a transmitting coil, a compensation coil and a receiving sensor are used, wherein the shapes of the transmitting coil and the compensation coil are regular shapes, and the shapes of the transmitting coil and the compensation coil are the same; the transmitting coil surrounds the compensation coil, and the compensation coil surrounds the receiving sensor; the transmitting coil and the compensation coil are reversely connected in series, and the two ends of the reverse series connection are connected to the positive output connection port and the negative output connection port of the transmitting system respectively, and the two ends of the receiving sensor are connected to the signal input end of the receiving system. A resistor R is connected in parallel at both ends of the compensation coil. The present application solves the problems existing in the two electromagnetic detection methods of time domain and frequency domain in the prior art, thereby overcoming the shortcomings of the primary field in the time domain being doped in the early moment of the secondary field response curve, causing the shallow information to be "annihilated" and the shallow detection "blind area" to be generated, and using the advantages of the frequency domain electromagnetic detection with strong anti-interference ability and large detection depth to solve the geological problems of shallow and ultra-shallow electromagnetic detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0019] Figure 1 It is a schematic diagram of the applicable area of ​​the device and method according to the embodiment of the present application.

[0020] Figure 2 is a schematic diagram of a primary field compensation device according to an embodiment of the present application.

[0021] Figure 3It is a connection diagram and an equivalent circuit diagram of a primary field compensation device according to an embodiment of the present application.

[0022] Figure 4 It is a schematic diagram of the transmission waveform of the transmission system according to an embodiment of the present application.

[0023] Figure 5 It is a schematic diagram of the data processing process of the receiving system in different time periods according to an embodiment of the present application.

[0024] Figure 6 It is a flow chart of a primary field compensation time-frequency electromagnetic detection method according to an embodiment of the present application. DETAILED DESCRIPTION

[0025] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0026] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0027] In this embodiment, a primary field compensation time-frequency electromagnetic detection device is provided, comprising: a transmitting coil, a compensation coil and a receiving sensor, wherein:

[0028] The shapes of the transmitting coil and the compensating coil are regular shapes, and the shapes of the transmitting coil and the compensating coil are the same; for example, the shapes of the transmitting coil and the compensating coil are one of the following: circle, rectangle, and regular polygon.

[0029] The transmitting coil surrounds the compensation coil, and the compensation coil surrounds the receiving sensor; for example, the receiving sensor is one of the following: a coil, a flux gate, and a magnetic bar.

[0030] The transmitting coil and the compensating coil are connected in reverse series, and the two ends of the reverse series connection are connected to the positive output wiring port and the negative output wiring port of the transmitting system respectively, and the two ends of the receiving sensor are connected to the signal input end of the receiving system.

[0031] A resistor R is connected in parallel at both ends of the compensation coil.

[0032] This embodiment solves the problems existing in the time domain and frequency domain electromagnetic detection methods in the prior art, thereby overcoming the disadvantages of the primary field in the time domain being doped in the early moments of the secondary field response curve, causing "annihilation" of shallow information and producing "blind spots" in shallow detection. The advantages of frequency domain electromagnetic detection, such as strong anti-interference ability and large detection depth, are utilized to solve geological problems in shallow and ultra-shallow electromagnetic detection.

[0033] There are many ways to obtain the resistance value of the resistor R. For example, the resistance value of the resistor R is configured so that under a predetermined environment, when the transmitting system transmits a current signal to the transmitting coil and the compensation coil, the resistance value of the resistor R can make the receiving signal of the receiving system infinitely close to zero. The predetermined environment is a shielded environment with relatively no interference and no magnetic field, and the device is suspended in the device.

[0034] The resistance value of the resistor R is configured to make the magnetic induction intensities of the transmitting coil and the compensation coil the same, and the directions of the magnetic induction intensities are opposite.

[0035] Optionally, the waveform emitted by the transmitting system is a mixed waveform of a unipolar pulse waveform and a bipolar pulse waveform. For example, the bipolar pulse waveform includes at least one of the following: a single frequency wave, a n Pseudo-random signal waveform, m-sequence waveform. Optionally, the period of the mixed wave generated by the transmitting system is T, and in the period T, the signal level is 0 for part of the time.

[0036] In this embodiment, a primary field compensation time-frequency electromagnetic detection method is also provided, using the above-mentioned device for detection. Figure 6 is a flow chart of a field compensation time-frequency electromagnetic detection method according to an embodiment of the present application, such as Figure 6 As shown, the process includes the following steps:

[0037] Step S602, the transmitting system generates a waveform, wherein the waveform is transmitted by the transmitting coil and the compensation coil;

[0038] Step S604, receiving a waveform through the receiving sensor;

[0039] Step S606: the receiving system performs electromagnetic detection according to the waveform received by the receiving sensor.

[0040] Through the above steps, the device in this embodiment can be used for detection, which overcomes the disadvantages of the primary field in the time domain being doped in the early moments of the secondary field response curve, causing "annihilation" of shallow information and producing a "blind spot" in shallow detection. The advantages of frequency domain electromagnetic detection, such as strong anti-interference ability and large detection depth, can be used to solve geological problems in shallow and ultra-shallow electromagnetic detection.

[0041] The following is an explanation in conjunction with an embodiment. The primary field compensation device provided in this embodiment includes a transmitting coil, a compensation coil, and a receiving sensor. The primary field compensation device is located in the same horizontal plane and is vertically coaxial. The shapes of the transmitting coil and the compensation coil of the primary field compensation device must be exactly the same and regular. Among them, the transmitting coil is located in the outermost layer and includes the compensation coil; the compensation coil is located in the middle layer and includes the receiving sensor; the receiving sensor is located in the innermost layer. The shapes of the transmitting coil and the compensation coil of the primary field compensation device include but are not limited to circular, square, and polygonal, and the receiving sensor includes but is not limited to coils, flux gates, and magnetic bars.

[0042] Among them, after the transmitting coil and the compensation coil in the primary field compensation device are connected in reverse series, the two ends are connected to the positive output wiring port and the negative output wiring port of the transmitting system respectively; the two ends of the receiving sensor are connected to the signal input end of the receiving system. A resistor R is connected in parallel at both ends of the compensation coil, and the resistance value of the resistor needs to be obtained through indoor calibration test according to the parameters and process of the primary field compensation device.

[0043] Through the primary field compensation parameter adjustment, process design, and the adjustment of the resistance value of the parallel resistor R at both ends of the compensation coil, the magnetic induction intensity of the transmitting coil and the compensation coil should strictly meet the following requirements:

[0044] |B 发射 |=|B 补偿 |

[0045] The transmitting system in this embodiment transmits a mixed waveform of a unipolar pulse waveform commonly used in the time domain and a bipolar pulse waveform commonly used in the frequency domain. The bipolar pulse waveform includes but is not limited to a single frequency wave, a n Pseudo-random signal waveform, m-sequence waveform, etc. The period of the mixed waveform emitted by the transmitting system is T, the first T / 3 period of the transmitted signal level is 0, the second T / 3 period of the transmitted bipolar pulse wave, and the third T / 3 period of the transmitted signal level is 0. The transmitting system and the receiving system are synchronized by GPS or high-precision and high-stability quartz crystal.

[0046] The working modes of the receiving system in this embodiment include: a verification mode and a measurement mode. These two modes are described below respectively.

[0047] When the receiving system works in the verification mode, the primary field compensation device is placed in a relatively interference-free and magnetic field-free environment. In the first T / 3 cycle, since the transmission signal is 0, the environmental noise waveform is recorded at this stage, and the noise spectrum analysis is performed, which is recorded as S0; in the second T / 3 cycle, since there is almost no target medium excitation response, there is only compensation residual, and the compensation residual spectrum analysis is performed at this stage, which is recorded as S1; in the third T / 3 cycle, since there is almost no target medium excitation response, the compensation residual and the environmental secondary field time domain waveform are recorded at this stage, which is recorded as S2. S1-S0 is used to obtain the compensation residual spectrum S1' after removing the environmental noise, and S3-S0 is used to obtain the compensation residual secondary field time domain waveform S2' after removing the environmental noise.

[0048] When the receiving system works in the measurement mode, the primary field compensation device is placed on the surface above the medium to be detected. In the first T / 3 period, since the transmission signal is 0, the environmental noise waveform is recorded at this stage, and the noise spectrum analysis is performed, which is recorded as V0; in the second T / 3 period, since there is an excitation response of the target medium, the excitation response spectrum analysis is performed at this stage, which is recorded as V1; in the third T / 3 period, since there is an excitation response of the target medium, the secondary field time domain waveform is recorded at this stage, which is recorded as V2. V1-V0-S1' is used to obtain the pure medium excitation response spectrum after removing the environmental noise and compensating the residual spectrum, and V2-V0-S2' is used to obtain the pure medium excitation response secondary field waveform V2' after removing the environmental noise and compensating the residual.

[0049] The present embodiment is described below in conjunction with the accompanying drawings. The present embodiment can be applied to Figure 1 The environment shown in Figure 1 The ultra-shallow and shallow areas below the mid-surface can be measured in the time domain, and the shallow and deep areas can be measured in the frequency domain. Figure 2 A field compensation device is shown, which includes a transmitting coil, a compensation coil, and a receiving sensor. Figure 2 As shown, the primary field compensation device is located in the same horizontal plane and vertically coaxially, and the shapes of the transmitting coil and the compensating coil of the primary field compensation device must be exactly the same and regular. Among them, the transmitting coil is located in the outermost layer, including the compensating coil; the compensating coil is located in the middle layer, including the receiving sensor; the receiving sensor is located in the innermost layer. The shapes of the transmitting coil and the compensating coil of the primary field compensation device include but are not limited to circular, square, and polygonal, and the receiving sensors include but are not limited to coils, flux gates, and magnetic rods. Among them, Figure 2(a) is a circular transmitting, compensating coil and circular receiving coil sensor, (b) is a circular transmitting, compensating coil and fluxgate (or magnetic bar) receiving sensor, (c) is a square transmitting, compensating coil and square receiving coil sensor, and (d) is a square transmitting, compensating coil and fluxgate (magnetic bar) receiving sensor.

[0050] Figure 3 This is a connection diagram and equivalent circuit diagram of a primary field compensation device, such as Figure 3 As shown, after the transmitting coil and the compensating coil in the primary field compensation device in this embodiment are connected in reverse series, the two ends are connected to the positive output wiring port and the negative output wiring port of the transmitting system respectively; the two ends of the receiving sensor are connected to the signal input end of the receiving system. A resistor R is connected in parallel at both ends of the compensating coil, and the resistance value of the resistor needs to be obtained through indoor calibration test according to the parameters and process of the primary field compensation device.

[0051] The calibration test method is: in a relatively interference-free, non-magnetic field shielding environment, the primary field compensation type is stably suspended, the transmitting system transmits a current signal of fixed frequency and amplitude to the transmitting coil and the compensation coil, and the receiving system measures the amplitude of the received signal through the receiving sensor. When the resistance value of the parallel resistor R is adjusted so that the amplitude of the received signal is infinitely close to zero, the resistance value is the determined resistance value of the parallel resistor R.

[0052] In this embodiment, through the adjustment of the parameters of the primary field compensation device, the process design, and the adjustment of the resistance value of the parallel resistor R at both ends of the compensation coil, the magnetic induction intensity of the transmitting coil and the compensation coil should strictly meet the following requirements:

[0053] |B 发射 |=|B 补偿 | (1)

[0054] Since the transmitting coil and the compensation coil are connected in series in reverse, the current directions are opposite, and the magnetic induction intensity directions are opposite, then:

[0055] B 发射 =-B 补偿 (2)

[0056] Take the circular coil as an example: suppose the number of turns of the circular transmitting coil is n 发射 , the radius of the transmitting coil is r 发射 , the vacuum magnetic permeability is μ0, the transmitting current is I, according to the Biot-Savart law, the magnetic induction intensity at the center of the transmitting coil can be derived:

[0057]

[0058] Assume the radius of the circular compensation coil:

[0059]

[0060] According to formula (1) (3), we can get:

[0061]

[0062] The transmitting system transmits a mixed waveform of the unipolar pulse waveform commonly used in the time domain and the bipolar pulse waveform commonly used in the frequency domain, such as Figure 4 Bipolar pulse waveforms include but are not limited to single frequency waves, based on a n Pseudo-random signal waveform (for example, this waveform is disclosed in patent numbers: CN201811309318.2, CN202010344733.2, CN202010344576.5, which will not be repeated here), m-sequence waveform. The period of the mixed waveform emitted by the transmitting system is T, the first T / 3 period emission signal level is 0, the second T / 3 period emits a bipolar pulse wave, and the third T / 3 period emission signal level is 0. The transmitting system and the receiving system are synchronized by GPS or high-precision and high-stability quartz crystal.

[0063] In this embodiment, the receiving system working modes include: verification mode, measurement mode, such as Figure 5 As shown, in the verification mode, the primary field compensation device is placed in a relatively interference-free and magnetic field-free environment. In the first T / 3 cycle, since the transmission signal is 0, the environmental noise waveform is recorded at this stage, and the noise spectrum analysis is performed, which is recorded as S0; in the second T / 3 cycle, since there is almost no target medium excitation response, there is only the compensation residue in the above process (adjusting the resistance value of the parallel resistor R can only make the amplitude of the compensated received signal infinitely close to zero, and due to the deformation of the coil, it is affected by factors such as temperature changes during use, and there is still compensation residue). At this stage, the compensation residue spectrum analysis is performed, which is recorded as S1; in the third T / 3 cycle, since there is almost no target medium excitation response, the compensation residue and the environmental secondary field time domain waveform are recorded at this stage, which is recorded as S2. S1-S0 is used to obtain the compensation residue spectrum S1' after removing the environmental noise, and S3-S0 is used to obtain the compensation residue secondary field time domain waveform S2' after removing the environmental noise.

[0064] like Figure 5As shown, in the measurement mode, the primary field compensation device is placed on the surface above the medium to be detected. In the first T / 3 period, since the transmission signal is 0, the environmental noise waveform is recorded at this stage, and the noise spectrum analysis is performed, which is recorded as V0; in the second T / 3 period, since there is an excitation response of the target medium, the excitation response spectrum analysis is performed at this stage, which is recorded as V1; in the third T / 3 period, since there is an excitation response of the target medium, the secondary field time domain waveform is recorded at this stage, which is recorded as V2. V1-V0-S1' is used to obtain the pure medium excitation response spectrum after removing the environmental noise and compensating the residual spectrum, and V2-V0-S2' is used to obtain the pure medium excitation response secondary field waveform V2' after removing the environmental noise and compensating the residual.

[0065] In the above embodiment, the disadvantages of the primary field in the time domain being doped in the early moments of the secondary field response curve, which causes the "annihilation" of shallow information and the creation of a "blind spot" in shallow detection, are overcome. The advantages of frequency domain electromagnetic detection, such as strong anti-interference capability and great detection depth, are utilized to solve geological problems in shallow and ultra-shallow electromagnetic detection.

[0066] In this embodiment, an electronic device is provided, including a memory and a processor. The memory stores a computer program, and the processor is configured to run the computer program to execute the method in the above embodiment.

[0067] The above program can be run in the processor, or it can be stored in the memory (or computer-readable medium), which includes permanent and non-permanent, removable and non-removable media. Information storage can be achieved by any method or technology. Information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, read-only compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined in this article, computer-readable media does not include temporary computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0068] These computer programs can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps of the functions specified in one or more blocks can be implemented by different modules corresponding to different steps.

[0069] This embodiment provides such a device or system.

[0070] The system or device is used to implement the functions of the method in the above-mentioned embodiment. Each module in the system or device corresponds to each step in the method, which has been explained in the method and will not be repeated here.

[0071] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A primary field compensation time-frequency electromagnetic detection device, characterized in that: include: Transmitting coil, compensation coil and receiving sensor, wherein, The shapes of the transmitting coil and the compensating coil are regular shapes, and the shapes of the transmitting coil and the compensating coil are the same; The transmitting coil surrounds the compensation coil, and the compensation coil surrounds the receiving sensor; The transmitting coil and the compensating coil are connected in reverse series, and the two ends of the reverse series connection are connected to the positive output connection port and the negative output connection port of the transmitting system respectively, and the two ends of the receiving sensor are connected to the signal input end of the receiving system; A resistor R is connected in parallel at both ends of the compensation coil; wherein the resistance value of the resistor R is configured such that under a predetermined environment, when the transmitting system transmits a current signal to the transmitting coil and the compensation coil, the resistance value of the resistor R can make the receiving signal of the receiving system infinitely close to zero; the resistance value of the resistor R is configured such that the magnetic induction intensities of the transmitting coil and the compensation coil are the same, and the directions of the magnetic induction intensities are opposite; Wherein, the period of the mixed wave generated by the transmitting system is T, and in the period T, the signal level is 0 for part of the time; wherein, the period of the mixed waveform emitted by the transmitting system is T, the emission signal level is 0 in the first T / 3 period, the bipolar pulse wave is emitted in the second T / 3 period, and the emission signal level is 0 in the third T / 3 period; the working modes of the receiving system include: verification mode and measurement mode; wherein, when the receiving system works in the verification mode, the primary field compensation time-frequency electromagnetic detection device is placed in a relatively interference-free and magnetic field-free environment; in the first T / 3 period, since the emission signal is 0, the environmental noise waveform is recorded at this stage, and the noise spectrum analysis is performed, which is recorded as S0; in the second T / 3 period, the compensation residual spectrum analysis is performed, which is recorded as S1; in the third T / 3 period, the compensation residual and the environmental secondary field time domain are recorded. waveform, recorded as S2; S1-S0 is used to obtain the compensated residual spectrum S1' after removing the environmental noise, and S2-S0 is used to obtain the compensated residual secondary field time domain waveform S2' after removing the environmental noise; when the receiving system works in the measurement mode, the primary field compensation time-frequency electromagnetic detection device is placed on the surface above the medium to be detected; in the first T / 3 period, since the transmission signal is 0, the environmental noise waveform is recorded, and the noise spectrum analysis is performed, recorded as V0; in the second T / 3 period, the excitation response spectrum analysis is performed, recorded as V1; in the third T / 3 period, the secondary field time domain waveform is recorded, recorded as V2; V1-V0-S1' is used to obtain the pure medium excitation response spectrum after removing the environmental noise and the compensated residual spectrum, and V2-V0-S2' is used to obtain the pure medium excitation response secondary field waveform V2' after removing the environmental noise and the compensated residual.

2. The device according to claim 1, characterized in that The shape of the transmitting coil and the compensation coil is one of the following: a circle and a regular polygon.

3. The device according to claim 1, characterized in that The receiving sensor is one of the following: a coil, a flux gate, and a magnetic bar.

4. A primary field compensation time-frequency electromagnetic detection method, characterized in that: The detection is performed using the device according to any one of claims 1 to 3, comprising: The transmitting system generates a waveform, wherein the waveform is transmitted by the transmitting coil and the compensation coil; receiving a waveform via the receiving sensor; The receiving system performs electromagnetic detection according to the waveform received by the receiving sensor.

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