A transient electromagnetic acquisition device and a transient electromagnetic signal acquisition method

Abstract

The present invention relates to the field of transient electromagnetic technology and discloses a transient electromagnetic acquisition device and transient electromagnetic signal acquisition method. The device comprises a triangular bracket with multiple antennas disposed at the top of the bracket, the antennas being rotatably connected to the top of the bracket; a transient electromagnetic sensor is connected to the triangular bracket, and the transient electromagnetic sensor comprises a hollow coil wrapped in a first housing. The hollow coil is connected to a battery and an amplifier, respectively, both of which are disposed below the hollow coil. The device dynamically adjusts the effective length and angle of the antenna when acquiring electromagnetic response signals, thereby improving the accuracy of electromagnetic response signal acquisition. The present invention has the beneficial effect of automatically adjusting the electromagnetic signal acquisition process according to changes in the acquisition environment, improving the accuracy of electromagnetic signal acquisition, and achieving precise exploration.

Description

Technical Field

[0001] The present invention relates to the field of transient electromagnetic technology, and in particular to a transient electromagnetic acquisition device and a transient electromagnetic signal acquisition method. Background Art

[0002] Transient electromagnetic (TEM) involves emitting a pulsed magnetic field underground using an ungrounded return line or grounded source. During the pauses between pulses, the secondary eddy current field is observed using a coil, magnetic probe, or grounded electrode. Simply put, TEM is an application of the law of electromagnetic induction. In recent years, TEM has been widely developed and applied in mineral exploration and engineering surveys, boasting strong penetration capabilities for both high- and low-resistance layers and deep exploration depths.

[0003] At present, when transient electromagnetic related equipment and instruments are used in the field, some special terrains will interfere with the acquisition of signals. At this time, the staff needs to adjust the acquisition equipment based on their rich experience to minimize the interference of the environment on the magnetic field response signal and achieve the purpose of accurate exploration. Although this method can improve the acquisition accuracy of transient electromagnetic signals, it also places high demands on the staff operating the acquisition equipment. For newcomers who have just started exploration work, they do not have the corresponding rich exploration experience reserves. When the environment interferes with the electromagnetic signal acquisition, they cannot use their experience to adjust the equipment, and thus cannot effectively guarantee the accuracy of transient electromagnetic signal acquisition.

[0004] Therefore, this project aims to develop a device that can self-adjust to ensure the accuracy of transient electromagnetic signal acquisition in different terrains and different working environments. Summary of the Invention

[0005] The present invention aims to provide a transient electromagnetic acquisition device and a transient electromagnetic signal acquisition method to solve the problem that the existing transient electromagnetic equipment cannot automatically adjust the acquisition accuracy during measurement.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a transient electromagnetic acquisition device, including a triangular bracket, with multiple antennas provided at the top of the triangular bracket, and the antennas are rotatably connected to the top of the triangular bracket; a transient electromagnetic sensor is connected to the triangular bracket, and the transient electromagnetic sensor includes a hollow coil, and the hollow coil is wrapped with a first shell. The hollow coil is connected to a battery and an amplifier respectively, and the battery and the amplifier are both arranged below the hollow coil.

[0007] The principles and advantages of this solution are as follows: in practical applications, a hollow coil is used to receive reflected electromagnetic signals. Different adjustment strategies are implemented for different acquisition environments and locations. Adjustment of the antenna is used to enhance signal reception strength, thereby improving electromagnetic signal acquisition accuracy. Compared to existing technologies, this solution offers advantages in that it can improve electromagnetic signal acquisition accuracy by adjusting the antenna angle and length in real time. Furthermore, by specifically selecting the acquisition terrain, it avoids signal loss caused by the terrain, thereby improving the acquisition accuracy of the transient electromagnetic acquisition device and increasing the efficiency of transient electromagnetic signal acquisition.

[0008] Preferably, as an improvement, a flange is provided at the upper end of the triangular bracket, and a plurality of first legs are connected to the flange, and each of the first legs is connected to a second leg.

[0009] Beneficial effect: By setting the first and second legs, the length and position of the legs can be adjusted, so that the transient electromagnetic acquisition device can be stably placed in different terrains, ensuring the accuracy of the device in collecting electromagnetic signals, thereby improving the application range of the transient electromagnetic acquisition device.

[0010] Preferably, as an improvement, the second leg is hingedly connected to the first leg.

[0011] Beneficial effect: The second leg is connected to the first leg in a hinged manner, which not only ensures the stability of the connection between the two legs, but also does not affect the extension size of the legs. Therefore, the transient electromagnetic signal acquisition device can be adapted to any field working terrain by arbitrarily changing the legs, thereby increasing the application range of the device.

[0012] Preferably, as an improvement, the antenna is a retractable antenna.

[0013] Beneficial effect: In order to ensure the signal collection strength, the antenna is set to a retractable antenna. By changing the effective effective length of the antenna, the auxiliary effect strength of the antenna on electromagnetic signal collection is improved, thereby enhancing the device's ability and accuracy to obtain electromagnetic signals.

[0014] The present invention also provides a method for acquiring transient electromagnetic signals, which uses the transient electromagnetic acquisition device as described above and includes the following steps:

[0015] Step S1, emitting a pulsed magnetic field underground, and then using a hollow coil and an antenna to collect the underground magnetic field response signal;

[0016] Step S2, adjusting the transient electromagnetic acquisition device according to different acquisition environments, acquiring a magnetic field response signal in real time during the adjustment process, and dynamically adjusting the weights of the coil signal and the antenna signal according to environmental changes to obtain a first magnetic field response signal;

[0017] Step S3: obtaining a first induced electromotive force from the first magnetic field response signal, amplifying the first induced electromotive force by an amplifier to obtain a second induced electromotive force, and sending the second induced electromotive force to a receiving device.

[0018] Through the coordinated collection of coils and antennas, accurate acquisition of electromagnetic signals can be achieved, and the antenna can be adjusted to different angles and effective lengths according to different environments. This can not only effectively ensure the accuracy of electromagnetic signal acquisition, but also effectively improve the acquisition range of electromagnetic signals, thereby enhancing the device's ability to acquire electromagnetic signals. On the other hand, the signals collected by the coils and antennas will also be weighted to further improve the acquisition capability and accuracy of electromagnetic signals.

[0019] Preferably, as an improvement, the transient electromagnetic acquisition device is adjusted according to different acquisition environments by first determining the location of the transient electromagnetic acquisition device, including determining whether the location is at the foot of the mountain, on the mountainside, or at the top of the mountain; then determining the altitude of the current location; and finally determining the slope of the acquisition point. The antenna is then adjusted based on the determination result.

[0020] Beneficial effects: The acquisition device can be intelligently adjusted according to different environments to better ensure the accuracy of electromagnetic signal acquisition. At the same time, it can also enable the device to reach the most ideal working state as soon as possible, save adjustment process time, and improve electromagnetic signal acquisition efficiency.

[0021] Preferably, as an improvement, the antenna is adjusted as follows:

[0022] If the transient electromagnetic acquisition device is located at the foot of a mountain, first adjust the angle of the first antenna to the first preset position, then adjust the angle of the second antenna to the second preset position, and finally adjust the angle of the third antenna to the third preset position;

[0023] If the transient electromagnetic acquisition device is located on the mountainside, first adjust the lengths of all antennas to a first length position, and then adjust the angles of the antennas to a first preset angle;

[0024] If the transient electromagnetic acquisition device is located at the top of a mountain, first adjust the lengths of all antennas to the second length position, then adjust the angles of the antennas close to the mountain side to the first angle position, and finally adjust the angles of the remaining antennas to the second angle position;

[0025] If the altitude of the current location of the transient electromagnetic acquisition device is within the first altitude range, adjusting the angles of all antennas to the planned positions simultaneously;

[0026] If the altitude of the current location of the transient electromagnetic acquisition device is within the second altitude range, first adjust the angle of the first antenna, then adjust the angles of the second antenna and the third antenna in sequence;

[0027] If the altitude of the current location of the transient electromagnetic acquisition device is within the third altitude range, first adjust the lengths of all antennas, then adjust the angle of the first antenna to the intermediate angle position, then adjust the angle of the second antenna to the second preset angle position, and finally adjust the angle of the third antenna to the third preset position;

[0028] If the slope of the current location of the transient electromagnetic acquisition device is within the preset range, the effective length of the triangular bracket is adjusted first, and then the angle and length of the antenna are adjusted; if it exceeds the preset range, the deflection angle of the triangular bracket is adjusted first, and then the angle and length of the antenna are adjusted.

[0029] Beneficial effects: The antenna is adjusted in a targeted manner according to the different conditions of the location of the acquisition device and the different conditions such as altitude and slope, so that the antenna can achieve the best acquisition state of transient electromagnetic signals, complete the acquisition of electromagnetic signals as quickly as possible, avoid the acquisition time being too long, which will lead to a greater impact of the earth's conductivity, enhance the intensity of the device's acquisition of electromagnetic signals, thereby improving the accuracy of signal acquisition, and realize targeted adjustment according to the different effects of different geographical environments on transient electromagnetic signals, thereby ensuring the smooth acquisition of transient electromagnetic signals.

[0030] Preferably, as an improvement, when acquiring transient electromagnetic signals, the signal acquisition is processed differently according to the different terrains of the acquisition point. If the acquisition point is located on a ridge, the antenna is retracted and shielded by a shielding device. If the acquisition point is located in a valley, the effective length of the antenna is increased.

[0031] Beneficial effects: Through the study of ridges and valleys, it was found that they have the greatest impact on electromagnetic signals. Therefore, during collection, the role of the collection antenna is changed according to the specific impact mode, thereby reducing the impact of ridges and valleys to a minimum range, ensuring the accuracy and intensity of transient electromagnetic signal collection.

[0032] Preferably, as an improvement, when the first induced electromotive force is obtained from the magnetic field response signal, the formula e=-jωNSB is used for conversion, where e is the induced electromotive force at both ends of the hollow coil; ω is the angular frequency of the earth's magnetic field; N is the number of turns of the hollow coil; S is the cross-sectional area of the horizontal plane surrounded by the hollow coil; and B is the magnetic field response signal.

[0033] Beneficial effect: This formula is used to convert the obtained magnetic field response signal into an induced electromotive force, which facilitates the subsequent digital analysis of the electromagnetic signal and further analyzes the geological conditions of the detection target. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a structural diagram of a transient electromagnetic acquisition device according to a first embodiment of the present invention.

[0035] Figure 2The figure is a flow chart of a first embodiment of a method for acquiring transient electromagnetic signals according to the present invention. DETAILED DESCRIPTION

[0036] The following is further described in detail through specific implementation methods:

[0037] The symbols in the drawings of the specification include: triangular bracket 1, transient electromagnetic sensor 2, antenna 3, air-core coil 4, first housing 5, battery 6, amplifier 7, flange 8, first leg 9, and second leg 10.

[0038] Example 1:

[0039] This embodiment is basically as shown in the attached Figure 1 As shown: A transient electromagnetic acquisition device includes a triangular bracket 1, which includes three symmetrically arranged legs and a flange 8 that serves as a load-bearing connection. The flange 8 is arranged at the upper end of the triangular bracket 1, and the lower end surface of the flange 8 is connected to three first legs 9, each of which is further hingedly connected to a retractable second leg 10; a transient electromagnetic sensor 2 is connected to the triangular bracket 1, and the transient electromagnetic sensor 2 includes a hollow coil 4, which is wrapped with a first shell 5. Three retractable antennas 3 are provided on the upper end of the first shell 5 at the top of the triangular bracket 1, and the antenna 3 is connected to the first shell 5 in a rotatable manner. The hollow coil 4 is connected to a battery 6 and an amplifier 7 respectively, and the battery 6 and the amplifier 7 are both arranged below the hollow coil 4.

[0040] As attached Figure 2 As shown, the present invention also provides a method for acquiring transient electromagnetic signals using the above-mentioned transient electromagnetic acquisition device, comprising the following steps:

[0041] Step S1, emitting a pulsed magnetic field underground, and then using the hollow coil 4 and antenna 3 to collect the underground magnetic field response signal;

[0042] Step S2, adjusting the transient electromagnetic acquisition device according to different acquisition environments, acquiring a magnetic field response signal in real time during the adjustment process, and dynamically adjusting the weights of the coil signal and the antenna 3 signal according to environmental changes to obtain a first magnetic field response signal;

[0043] In step S3, a first induced electromotive force is obtained from the first magnetic field response signal, the first induced electromotive force is amplified by the amplifier 7 to obtain a second induced electromotive force, and the second induced electromotive force is sent to a receiving device.

[0044] When adjusting according to the collection environment, the position of the transient electromagnetic acquisition device is first determined, including whether it is at the foot of the mountain, on the mountainside, or on the top of the mountain. Then, the altitude of the current location is determined, and finally, the slope of the collection point is determined. Then, the antenna 3 is adjusted according to the judgment result.

[0045] If the transient electromagnetic acquisition device is located at the foot of the mountain, first adjust the angle of the first antenna to the first preset position, that is, perpendicular to the ground; then adjust the angle of the second antenna to the second preset position, that is, the angle to the ground is 60 degrees; finally, adjust the angle of the third antenna to the third preset position, that is, the angle to the ground is 45 degrees;

[0046] If the transient electromagnetic acquisition device is located on the mountainside, first adjust the lengths of all antennas 3 to the first length position, and then adjust the angles of the three antennas to the first preset angle, that is, the angles between the three antennas are 120 degrees and 75 degrees to the ground;

[0047] If the transient electromagnetic acquisition device is located on the top of a mountain, first adjust the lengths of all antennas 3 to the second length position, then adjust the angles of the antennas 3 close to the mountain side to 15 degrees from the ground, and finally adjust the angles of the remaining antennas 3 to 45 degrees from the ground;

[0048] If the altitude of the current location of the transient electromagnetic acquisition device is within the first altitude interval of 2000 meters, the angles of all antennas 3 are adjusted to the planned positions at the same time, that is, 60 degrees to the ground and 120 degrees between the three antennas 3;

[0049] If the altitude of the current location of the transient electromagnetic acquisition device is within the second altitude range of 2000-4000 meters, first adjust the angle of the first antenna to 80 degrees with the ground, and then after 5 seconds, adjust the angles of the second antenna and the third antenna in sequence to 80 degrees with the ground;

[0050] If the altitude of the current location of the transient electromagnetic acquisition device is above 4000 meters in the third altitude range, first adjust the lengths of all antennas 3 to the maximum effective length, then adjust the angle of the first antenna to the intermediate angle position, that is, 45 degrees to the ground, then adjust the angle of the second antenna to 72 degrees to the ground, and finally adjust the angle of the third antenna to 90 degrees to the ground;

[0051] If the slope of the current location of the transient electromagnetic acquisition device is within the preset range of 60 degrees, first adjust the effective length of the triangular bracket 1, and then adjust the angle and length of the antenna 3; if the slope exceeds 60 degrees, first adjust the deflection angle of the triangular bracket 1, and then adjust the angle and length of the antenna 3.

[0052] After collecting the magnetic field response signal, when obtaining the first induced electromotive force from the first magnetic field response signal, the formula e=-jωNSB is used for conversion, where e is the induced electromotive force at both ends of the hollow coil 4; ω is the angular frequency of the earth's magnetic field; N is the number of turns of the hollow coil 4; S is the cross-sectional area of the horizontal plane surrounded by the hollow coil 4; and B is the magnetic field response signal.

[0053] In this embodiment, the exploration site is selected on the mountainside with an altitude within the second altitude range, and the slope of the location where the transient electromagnetic signal acquisition device is placed is within a preset range of 60 degrees.

[0054] When using a transient electromagnetic acquisition device to collect electromagnetic response signals after emitting a pulsed magnetic field into the ground, anti-interference equipment adjustments need to be made for different collection environments. In the past, this was highly dependent on the operator's rich exploration work experience. Now, different adjustment strategies are pre-set according to different geographical environments and collection environments. When collecting transient electromagnetic signals, the signal collection method can be automatically adjusted in real time. This not only breaks away from the constraints of work experience, but also enables the signal collection adjustment to be completed quickly and accurately, realizing the precise collection of transient electromagnetic response signals and greatly improving the accuracy of geological exploration.

[0055] The specific implementation process of this embodiment is as follows:

[0056] The first step is to select the exploration target point, then extend the triangular bracket 1 of the transient electromagnetic acquisition device, use the cooperation of the first leg 9 and the second leg 10 to stabilize the transient electromagnetic acquisition device, and then use the transmitter to emit a pulsed magnetic field into the ground.

[0057] In the second step, the hollow coil 4 and antenna 3 of the transient electromagnetic sensor 2 are used to collect the underground magnetic field response signal, and the transient electromagnetic acquisition device is adjusted according to different acquisition environments. First, the position of the transient electromagnetic acquisition device is judged, including whether the position is at the foot of the mountain, the mountainside or the top of the mountain, then the altitude of the current position is judged, and finally the slope of the acquisition point is judged. According to the judgment that the current position is at the mountainside, the altitude is within the second altitude range and the slope of the acquisition point is within the preset range of 60 degrees; first adjust the effective length of the triangular bracket 1, then adjust the length of all antennas 3 to the first length position, and then adjust the angle of the three antennas to the first preset angle, that is, the angle between the three antennas is 120 degrees and 75 degrees to the ground; 3 seconds after the adjustment is completed, adjust the angle of the first antenna to 80 degrees to the ground, and after 5 seconds, adjust the angle of the second antenna and the third antenna to 80 degrees to the ground in turn.

[0058] In the third step, during the adjustment process, the hollow coil 4 and antenna 3 are used to obtain the magnetic field response signal in real time, and the weights of the coil signal and the antenna 3 signal are dynamically adjusted according to environmental changes to obtain the first magnetic field response signal. Finally, the first magnetic field response signal is converted into the first induced electromotive force using the formula e=-jωNSB, and the first induced electromotive force is amplified by the amplifier 7 to obtain the second induced electromotive force, and the second induced electromotive force is sent to the receiving device.

[0059] With the development and application of transient electromagnetics in fields such as geological exploration, and the premise that the accuracy of geological requirements is getting higher and higher, in order to ensure, the requirements for devices for acquiring transient electromagnetic signals are also getting higher and higher. Therefore, the improvement of transient electromagnetic signal acquisition devices has always been a hot topic. At present, improvements to the devices are generally concentrated on improving the placement mechanism of the devices so that the devices can adapt to more field terrains. In view of the complex working environment in the field, in order to effectively avoid the interference of the environment on the electromagnetic signals and improve the accuracy of signal acquisition, it is often necessary for staff to adjust the signal acquisition device in real time based on work experience, so as to ensure the accuracy of the acquisition of electromagnetic response signals and achieve the purpose of accurate exploration. However, such acquisition method is not conducive to large-scale promotion, because for newcomers who have just started this work, there is no work experience to serve as a reference for adjustment, which makes it difficult to achieve high-precision geological exploration.

[0060] In this solution, an antenna 3 is set on the top of the triangular bracket 1, and a preset adjustment strategy of the antenna 3 in different collection environments is used, such as the judgment of the foot of the mountain, the middle of the mountain and the top of the mountain, as well as the judgment of the geographical altitude and slope of the location. By changing the extension length of the antenna 3 and the angle of the antenna 3, and coordinating the triangular support and the hollow coil 4, the electromagnetic response signal is collected, and the sensitivity and accuracy of the device for transient electromagnetic signal collection are adjusted in real time to avoid adverse effects on the signal collection of the hollow coil 4 due to the complex environment of the field work. This not only ensures the smooth collection of electromagnetic signals, but also avoids the loss of the collected signal caused by the influence of the terrain through the targeted selection of the collection terrain, thereby improving the collection accuracy of the transient electromagnetic acquisition device and effectively improving the collection efficiency of transient electromagnetic signals.

[0061] Example 2:

[0062] This embodiment is basically the same as the first embodiment, except that: when acquiring the magnetic field response signal, the weights of the coil signal and the antenna 3 signal are dynamically adjusted according to environmental changes. If the adjustment angle range of antenna 3 does not exceed 30 degrees, the coil signal accounts for 70% and the antenna 3 signal accounts for 30% when collecting the electromagnetic response signal; if the adjustment angle range of antenna 3 is greater than 30 degrees, the coil signal accounts for 40% and the antenna 3 signal accounts for 60% when collecting the electromagnetic response signal.

[0063] The specific implementation process of this embodiment is the same as that of the first embodiment, except that:

[0064] In the third step, during the adjustment process, the hollow coil 4 and antenna 3 are used to obtain the magnetic field response signal in real time, and the weights of the coil signal and the antenna 3 signal are dynamically adjusted according to environmental changes, where the coil signal accounts for 40% and the antenna 3 signal accounts for 60%, to obtain the first magnetic field response signal. Finally, the first magnetic field response signal is converted into a first induced electromotive force using the formula e=-jωNSB, and the first induced electromotive force is amplified by the amplifier 7 to obtain a second induced electromotive force, and the second induced electromotive force is sent to the receiving device.

[0065] Taking into account the complexity and variability of the environment at the collection point, in order to ensure the accuracy of electromagnetic response signal collection, the weights of the signals collected by the hollow coil 4 and the antenna 3 are adjusted in real time to ensure the effectiveness of the collected electromagnetic response signals, further improve the accuracy of acquiring transient electromagnetic signals, and improve the geological exploration effect.

[0066] Example 3:

[0067] This embodiment is basically the same as the first embodiment, except that when acquiring transient electromagnetic signals, different signal acquisition processes are performed according to the different terrains of the acquisition points. If the acquisition point is located on a ridge, the antenna 3 is retracted and shielded by a shielding device. If the acquisition point is located in a valley, the effective length of the antenna 3 is increased.

[0068] The specific implementation process of this embodiment is the same as that of the first embodiment, except that:

[0069] In the second step, the hollow coil 4 and antenna 3 of the transient electromagnetic sensor 2 are used to collect the underground magnetic field response signal, and the transient electromagnetic acquisition device is adjusted according to different acquisition environments. First, the location of the transient electromagnetic acquisition device is determined, including whether it is at the foot of the mountain, the mountainside, or the top of the mountain. Then, the altitude of the current location is determined. Finally, the slope of the acquisition point is determined. Based on the current location being at the mountainside, the altitude is within the second altitude range, and the slope of the acquisition point is within the preset range of 60 degrees, the effective length of the triangular bracket 1 is first adjusted, the lengths of all antennas 3 are adjusted to the first length position, and the angles of the three antennas are adjusted to the first preset angle, that is, the angles between the three antennas are 120 degrees and 75 degrees to the ground. Three seconds after the adjustment is completed, the angle of the first antenna is adjusted to 80 degrees to the ground. After 5 seconds, the angles of the second antenna and the third antenna are adjusted in sequence to 80 degrees to the ground. Finally, the location of the acquisition point is determined. If it is on the ridge, the antenna 3 is retracted and shielded by the shielding device. If the acquisition point is in the valley, the effective length of the antenna 3 is increased.

[0070] Both ridge and valley terrain can cause a certain degree of interference to the transient electromagnetic response signal. Valley terrain of the same geometric size has a greater impact on the electromagnetic response than ridge terrain. The impact of valley terrain on the electromagnetic response is to reduce the secondary field response within a certain time period, while ridge terrain enhances the secondary field response within a certain time period. Therefore, different adjustments to antenna 3 for ridge and valley terrain can minimize the impact of the terrain and improve the accuracy of transient electromagnetic response signal acquisition.

[0071] Example 4:

[0072] This embodiment is basically the same as the first embodiment, except that: when collecting electromagnetic signals, another identical transmitting wireframe is placed symmetrically with the original transmitting wireframe at the center of the interference source to control interference from man-made facilities. This measure is used to minimize interference signals.

[0073] The specific implementation process of this embodiment is the same as that of the first embodiment, except that:

[0074] The first step is to select the exploration target point, then extend the triangular bracket 1 of the transient electromagnetic acquisition device, use the cooperation of the first leg 9 and the second leg 10 to stabilize the transient electromagnetic acquisition device, and then use the transmitter to emit a pulsed magnetic field into the ground. At the same time, add anti-interference equipment near the test target point, and place another identical transmitting wire frame at a position symmetrical to the original transmitting wire frame with the artificial interference source as the center to emit the pulsed magnetic field.

[0075] When using transient electromagnetic method to operate in the field, many interferences will be encountered. The most common one is the interference of man-made facilities, and the other is electromagnetic noise. In order to avoid interference sources from interfering with the collection of transient electromagnetic signals, another identical transmitting wire frame is placed in a position symmetrical to the original transmitting wire frame with the artificial interference source as the center to shield the interference, thereby improving the signal collection capability and accuracy, and ensuring the smooth collection of transient electromagnetic signals.

[0076] The above is only an embodiment of the present invention, and the common knowledge such as the specific technical solutions and / or characteristics in the solution are not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the description can be used to interpret the content of the claims.

Claims

1. A method for acquiring transient electromagnetic signals, characterized in that: A transient electromagnetic acquisition device is used; The transient electromagnetic acquisition device includes a triangular bracket, a plurality of antennas are provided at the top of the triangular bracket, and the antennas are rotatably connected to the top of the triangular bracket; a transient electromagnetic sensor is connected to the triangular bracket, and the transient electromagnetic sensor includes a hollow coil, and the hollow coil is wrapped with a first shell. The hollow coil is respectively connected to a battery and an amplifier, and the battery and the amplifier are both arranged below the hollow coil; The method comprises the following steps: Step S1, emitting a pulsed magnetic field underground, and then using a hollow coil and an antenna to collect the underground magnetic field response signal; Step S2, adjusting the transient electromagnetic acquisition device according to different acquisition environments, acquiring a magnetic field response signal in real time during the adjustment process, and dynamically adjusting the weights of the coil signal and the antenna signal according to environmental changes to obtain a first magnetic field response signal; Step S3, obtaining a first induced electromotive force from the first magnetic field response signal, amplifying the first induced electromotive force using an amplifier to obtain a second induced electromotive force, and sending the second induced electromotive force to a receiving device; The adjustment of the transient electromagnetic acquisition device according to different acquisition environments is as follows: first, the location of the transient electromagnetic acquisition device is determined, including whether it is at the foot of the mountain, on the mountainside, or at the top of the mountain; then, the altitude of the current location is determined; and finally, the slope of the acquisition point is determined, and then the antenna is adjusted according to the determination results; The antenna is adjusted as follows: If the transient electromagnetic acquisition device is located at the foot of a mountain, first adjust the angle of the first antenna to the first preset position, then adjust the angle of the second antenna to the second preset position, and finally adjust the angle of the third antenna to the third preset position; If the transient electromagnetic acquisition device is located on the mountainside, first adjust the lengths of all antennas to a first length position, and then adjust the angles of the antennas to a first preset angle; If the transient electromagnetic acquisition device is located at the top of a mountain, first adjust the lengths of all antennas to the second length position, then adjust the angles of the antennas close to the mountain side to the first angle position, and finally adjust the angles of the remaining antennas to the second angle position; If the altitude of the current location of the transient electromagnetic acquisition device is within the first altitude range, adjusting the angles of all antennas to the planned positions simultaneously; If the altitude of the current location of the transient electromagnetic acquisition device is within the second altitude range, first adjust the angle of the first antenna, then adjust the angles of the second antenna and the third antenna in sequence; If the altitude of the current location of the transient electromagnetic acquisition device is within the third altitude range, first adjust the lengths of all antennas, then adjust the angle of the first antenna to the intermediate angle position, then adjust the angle of the second antenna to the second preset angle position, and finally adjust the angle of the third antenna to the third preset position; If the slope of the current location of the transient electromagnetic acquisition device is within the preset range, the effective length of the triangular bracket is adjusted first, and then the angle and length of the antenna are adjusted; if it exceeds the preset range, the deflection angle of the triangular bracket is adjusted first, and then the angle and length of the antenna are adjusted.

2. The method for acquiring transient electromagnetic signals according to claim 1, wherein: A flange is provided at the upper end of the triangular bracket, and a plurality of first legs are connected to the flange, and each of the first legs is connected to a second leg.

3. The method for acquiring transient electromagnetic signals according to claim 2, wherein: The second supporting leg is hingedly connected to the first supporting leg.

4. The method for acquiring transient electromagnetic signals according to claim 3, wherein: The second supporting leg is a retractable second supporting leg.

5. The method for acquiring transient electromagnetic signals according to claim 1, wherein: The antenna is a retractable antenna.

6. The method for acquiring transient electromagnetic signals according to claim 1, wherein: When acquiring transient electromagnetic signals, different signal processing is performed according to the different terrain of the collection point. If the collection point is located on a ridge, the antenna is retracted and shielded using a shielding device. If the collection point is located in a valley, the effective length of the antenna is increased.

7. The method for acquiring transient electromagnetic signals according to claim 1, wherein: When the first induced electromotive force is obtained from the first magnetic field response signal, the formula e=-jωNSB is used for conversion, where e is the induced electromotive force at both ends of the hollow coil; ω is the angular frequency of the earth's magnetic field; N is the number of turns of the hollow coil; S is the cross-sectional area of the plane surrounded by the hollow coil; B is the magnetic field response signal.

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