Antenna, detection device and detection system

Abstract

The invention provides an antenna, which comprises a main receiving wire frame and at least one sub-receiving wire frame, which are used for receiving an electromagnetic response signal, wherein a first included angle larger than 0 degree is formed between the normal direction of any one of the at least one sub-receiving wireframe and the normal direction of the main receiving wireframe, and the degree of the first included angle is determined according to the target detection aperture of the antenna. According to the antenna provided by the invention, the normal direction included angle between the sub-receiving wire frame and the main receiving wire frame is adjusted, so that the electromagnetic detection data received by the sub-receiving wire frame can be utilized to correct the electromagnetic data received by the main receiving wire frame, and the influence of a volume effect on a transient electromagnetic method is reduced.

Description

Technical Field

[0001] The present application relates to the field of electromagnetic detection, and in particular to an antenna, a detection device and a detection system. Background Art

[0002] Transient electromagnetic method (TEM) is a time domain artificial source electromagnetic detection method based on the law of electromagnetic induction. It has the advantages of being portable and easy to use, long detection distance, good coupling with geological bodies, sensitive response to low-resistance bodies and not being affected by their occurrence. In recent years, it has been widely used in mineral resource exploration, water resource exploration, engineering geological survey and geological disaster prediction.

[0003] From the "smoke ring effect" of TEM, it can be seen that the secondary field received at any time can be equivalent to the magnetic field generated by a circular current at the receiving antenna. At the zero moment when the transmitting current is turned off, the equivalent current loop has a similar shape and a similar position to the transmitting antenna. As time goes by, the current loop continues to spread forward and outward at a certain angle, and its shape gradually tends to be circular. Therefore, the area that can be effectively detected using a conventional planar transceiver wireframe is a cone that continues to extend outward over time, and has a large radial coverage of the geological body in the middle and late times, resulting in the low-resistance anomaly area in the TEM inversion results being often larger than the actual situation, and the detection resolution is low. How to reduce the impact of this volume effect on transient electromagnetic method is an urgent problem to be solved. Summary of the invention

[0004] The present application provides an antenna, a detection device and a detection system, which use the signal received by the sub-receiving wire frame in the antenna to correct the signal received by the main receiving wire frame, thereby reducing the influence of the volume effect on the transient electromagnetic method and improving the detection resolution.

[0005] In a first aspect, an antenna is provided, comprising: a main receiving wire frame and at least one sub-receiving wire frame, for receiving an electromagnetic response signal; wherein a normal direction of any one of the at least one sub-receiving wire frame has a first angle greater than 0 degrees with a normal direction of the main receiving wire frame, and the degree of the first angle is determined according to a target detection aperture of the antenna.

[0006] In the antenna provided in the present application, by adjusting the normal direction angle between the sub-receiving wireframe and the main receiving wireframe, the electromagnetic detection data received by the sub-receiving wireframe can be used to correct the electromagnetic data received by the main receiving wireframe, thereby reducing the influence of the volume effect on the transient electromagnetic method.

[0007] In combination with the first aspect, in some implementations of the first aspect, the first angle is further determined according to the inherent detection aperture of the main receiving wireframe. The inherent detection aperture φ' may be equivalent to a specific degree, such as 43°. In some implementations, the inherent detection aperture φ' may also be determined according to other methods, thereby determining the first angle θ i .

[0008] In combination with the first aspect, in some implementations of the first aspect, when the target detection aperture is greater than 0° and less than 43°, the relationship between the first angle and the target detection aperture satisfies θ i =φ+43°; when the target detection aperture is greater than or equal to 43° and less than 90°, the first angle satisfies 86°≤θ i <90°; where φ is the target detection aperture, θ i is the first angle, the value range of i is 1, 2…, N, and N is the number of at least one sub-receiving wireframe.

[0009] In combination with the first aspect, in some implementations of the first aspect, when the target detection aperture is greater than 0° and smaller than the target detection aperture, the relationship between the first angle and the target detection aperture satisfies θ i =φ+φ′; when the target detection aperture is greater than or equal to the target detection aperture and less than 90°, the first angle satisfies 2φ′≤θ i <90°; where φ is the target detection aperture, θ i is the first angle, the value range of i is 1, 2…, N, and N is the number of at least one sub-receiving wireframe.

[0010] In conjunction with the first aspect, in some implementations of the first aspect, the center points of any sub-receiving wireframes in at least one sub-receiving wireframe do not overlap. When the antennas are arranged in this way, the observation area of ​​any sub-receiving wireframe is different, which can avoid calibration errors.

[0011] In combination with the first aspect, in some implementations of the first aspect, on the plane where the main receiving wireframe is located, a projection of an area enclosed by any one of the at least one sub-receiving wireframes overlaps with an area enclosed by the main receiving wireframe. Thus, the detection aperture of the antenna can be further reduced by using the signal data received by the sub-receiving wireframes.

[0012] In combination with the first aspect, in some implementations of the first aspect, at least one sub-receiving wireframe includes a first sub-receiving wireframe and a second sub-receiving wireframe, wherein an area enclosed by the first sub-receiving wireframe and an area enclosed by the main receiving wireframe have a first intersection line, an area enclosed by the second sub-receiving wireframe and an area enclosed by the main receiving wireframe have a second intersection line, and the first intersection line and the second intersection line are parallel. Thus, a survey line is arranged for a survey area, and the detection aperture is reduced in two directions in the survey line, thereby reducing the influence of the volume effect on the transient electromagnetic method.

[0013] In combination with the first aspect, in some implementations of the first aspect, at least one sub-receiving wireframe further includes a third sub-receiving wireframe and a fourth sub-receiving wireframe, wherein the area enclosed by the third sub-receiving wireframe and the area enclosed by the main receiving wireframe have a third intersection line, the area enclosed by the fourth sub-receiving wireframe and the area enclosed by the main receiving wireframe have a fourth intersection line, and the third intersection line and the fourth intersection line intersect. Thus, two measuring lines are arranged for one measuring area, the detection aperture is reduced in two directions, and the influence of the volume effect on the transient electromagnetic method is reduced.

[0014] In combination with the first aspect, in some implementations of the first aspect, the antenna further includes a transmitting wireframe for transmitting an electromagnetic detection signal, wherein the normal of the transmitting wireframe coincides with the normal of the main receiving wireframe. That is, by determining the relationship between the transmitted electrical detection signal and the received electromagnetic signal, the signal received by the sub-receiving wireframe can correct the signal received by the main receiving wireframe, thereby enabling the antenna to achieve the purpose of the target detection aperture.

[0015] In some implementations, the transmitting wireframe has the same shape and size as the main receiving wireframe, and the transmitting wireframe contacts the main receiving wireframe. When the antenna is arranged in this way, the electromagnetic response signal is received with the greatest influence of the primary field, which is suitable for medium and long-distance target detection; or the plane where the transmitting wireframe is located is coplanar with the plane where the main receiving wireframe is located, and the center point of the transmitting wireframe coincides with the center point of the main receiving wireframe. When the antenna is arranged in this way, the electromagnetic response signal is received with a moderate influence of the primary field, and the detection blind area at close range is small when detecting targets; or the plane where the transmitting wireframe is located is parallel to the plane where the main receiving wireframe is located and there is a gap between them. When the antenna is arranged in this way, the electromagnetic signal is collected with the least influence of the primary field, which is suitable for close-range target detection.

[0016] In a second aspect, a detection device is provided, comprising an antenna as described in any aspect of the first aspect, wherein: a transmitter is electrically connected to a transmitting wire frame, the transmitter is used to generate an excitation current, the excitation current is input into the transmitting wire frame so that the transmitting wire frame transmits an electromagnetic detection signal; a receiver is electrically connected to a main receiving wire frame and at least one sub-receiving wire frame to obtain electromotive force data of the electromagnetic response signal.

[0017] In combination with the second aspect, in certain implementations of the second aspect, the receiver includes a correction circuit, wherein: the correction circuit includes multiple circuit channels, the multiple circuit channels are decoupled, the wire frames in the main receiving wire frame and at least one sub-receiving wire frame correspond one-to-one to the circuit channels in the multiple circuit channels, in which case, each receiving wire frame included in the antenna independently transmits electromotive force data to the receiver.

[0018] In combination with the second aspect, in certain implementations of the second aspect, the correction circuit includes a circuit channel, the main receiving wire frame and at least one sub-receiving wire frame are connected in series, the main receiving wire frame and at least one sub-receiving wire frame correspond to one circuit channel, in which case, the physical connection between the receiving wire frames included in the antenna transmits the electromotive force to the receiver together.

[0019] In conjunction with the second aspect, in certain implementations of the second aspect, the correction circuit is used to subtract the electromotive force data of the circuit channel corresponding to the main receiving wire frame from the electromotive force data of the circuit channel corresponding to at least one sub-receiving wire frame, so that when the angle between the main receiving wire frame and the sub-receiving wire frame is not fixed or fixed, the correction circuit is used to implement correction processing of the received signal.

[0020] In conjunction with the second aspect, in some implementations of the second aspect, the winding direction of the main receiving wire frame is opposite to the winding direction of the sub-receiving wire frame, so that the received signal can be corrected directly by using the physical connection of each receiving wire frame in the antenna.

[0021] In combination with the second aspect, in some implementations of the second aspect, the detection device further includes a bracket, wherein: the bracket is used to move the wire frame in the antenna; the receiver further includes a compass, the bracket is electrically connected to the compass, and the compass is electrically connected to the correction circuit, the compass is used to record the posture information of the wire frame included in the antenna, and transmit the posture information to the correction circuit; the correction circuit further includes a gain module, the gain module is arranged in the circuit channel, and the gain module is used to perform intensity gain on the current in the circuit channel corresponding to the sub-receiving wire frame according to the posture information of the sub-receiving wire frame. Thus, the gain module in the circuit is used to implement weighted processing of the received signals of each sub-receiving wire frame.

[0022] In conjunction with the second aspect, in some implementations of the second aspect, the size and number of turns of the sub-receiving wireframe are determined according to the posture information of the sub-receiving wireframe. Thus, the physical parameters of the wireframe can be used to implement weighted processing of the received signals of each sub-receiving wireframe.

[0023] In a third aspect, a detection system is provided, comprising an antenna system as described in any aspect of the second aspect and a host computer, wherein the host computer is used to control a transmitter and a receiver, and the host computer is also used to obtain electromotive force data and process the electromotive force data to obtain the resistivity of the detection target. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of an antenna provided in an embodiment of the present application.

[0025] Figure 2 It is a structural schematic diagram of another antenna provided in an embodiment of the present application.

[0026] Figure 3 It is a structural schematic diagram of another antenna provided in an embodiment of the present application.

[0027] Figure 4 It is a schematic diagram of the principle of using an antenna to reduce the detection aperture provided in an embodiment of the present application.

[0028] Figure 5 It is a structural schematic diagram of a detection device provided in an embodiment of the present application.

[0029] Figure 6 It is a structural schematic diagram of a correction circuit provided in an embodiment of the present application.

[0030] Figure 7 It is a structural schematic diagram of a detection system provided in an embodiment of the present application.

[0031] Figure 8 This is a schematic diagram of an apparent resistivity profile result provided in an embodiment of the present application.

[0032] Fig. 9 It is a schematic diagram of an application scenario applicable to an antenna and a detection device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] The technical solution in this application will be described below in conjunction with the accompanying drawings.

[0034] Transient electromagnetic method (TEM) is a time domain artificial source electromagnetic detection method based on the law of electromagnetic induction. It has the advantages of being portable and easy to use, long detection distance, good coupling with geological bodies, sensitive response to low-resistance bodies and not being affected by their occurrence. In recent years, it has been widely used in mineral resource exploration, water resource exploration, engineering geological survey and geological disaster prediction.

[0035] The TEM detection device is generally composed of components such as a host computer, a transmitter, a receiver, a transmitting antenna and a receiving antenna. The transmitting and receiving antennas usually adopt a circular or rectangular plane multi-turn wire frame, and the layout methods include the same point loop, the separated loop and the large fixed source loop. The wire frame can also be understood as an electromagnetic induction coil. The wire frame can be wound by a wire in a single direction. Among them, the detection process of TEM can be divided into three stages: transmission, induction and reception. Transmission stage: disconnect the stable current loaded in the transmitting antenna, and the stable primary magnetic field in the surrounding space disappears, that is, an electromagnetic detection signal is sent to the surrounding space. Induction stage: due to the drastic change of the primary field, an induced eddy current will be stimulated in the geological body in the detection area to maintain the original magnetic field, that is, a secondary magnetic field is generated. Reception stage: the induced current decays over time due to the heat loss of the medium. The receiving antenna is used to receive the electromagnetic response signal, and the corresponding attenuation process of the secondary field is observed. The electrical distribution of the geological body in the detection area is analyzed according to the received induced electromotive force data, and the low-resistance anomaly is qualitatively and quantitatively evaluated.

[0036] From the "smoke ring effect" of TEM, it can be seen that the secondary field received at any time can be equivalent to the magnetic field generated by a circular current at the receiving antenna. At the zero moment when the transmitting current is turned off, the equivalent current loop has a similar shape and a similar position to the transmitting antenna. As time goes by, the current loop continues to spread forward and outward at a certain angle, and its shape gradually tends to be circular. Therefore, the area that can be effectively detected using a conventional planar transceiver wireframe is a cone that continues to extend outward over time, and has a large radial coverage of the geological body in the middle and late times, resulting in the low-resistance anomaly area in the TEM inversion results being often larger than the actual situation, and the detection resolution is low. How to reduce the impact of this volume effect on transient electromagnetic method is an urgent problem to be solved.

[0037] Based on the above problems, the present application provides an antenna, a detection device and a detection system, which corrects the signal received by the main receiving frame by utilizing the signal received by the sub-receiving frame in the antenna, thereby reducing the influence of the volume effect on the transient electromagnetic method and improving the detection resolution.

[0038] Figure 1 is a schematic diagram of the structure of an antenna provided in an embodiment of the present application. Figure 1 As shown, the antenna includes:

[0039] Main receiving wireframe R X0 and at least one sub-receiving wireframe R X1 , …, R Xn , n is greater than or equal to 1. Figure 1 The figure shows a sub-receiving wireframe R X1 Main receiving wireframe R X0and at least one sub-receiving wireframe for receiving an electromagnetic response signal.

[0040] The normal direction of any one of the at least one sub-receiving wireframes has a first angle θ greater than 0 degrees with the normal direction of the main receiving wireframe. i , the first angle θ i The degree is determined according to the target detection aperture φ of the antenna. The detection aperture can be understood as the angle between the effective detection boundary of the transmitting wireframe or the receiving wireframe and the center normal of the antenna. The center normal of the antenna or the wireframe in the antenna and the normal direction can be determined according to Ampere's law.

[0041] In some implementations, the first angle θ i The degree of can be determined according to the inherent detection aperture φ' of the main receiving wireframe and the target detection aperture φ. The inherent detection aperture φ' can be equivalent to a specific degree, such as 43°. In some implementations, the inherent detection aperture φ' can also be determined according to other methods, so as to determine the first angle θ i .

[0042] In some implementations, the first angle may be determined as:

[0043]

[0044] Where φ is the target detection aperture, φ' is the inherent detection aperture of the main receiving wireframe, and θ i is the first angle, the value range of i is 1, 2…, n, and n is the number of at least one sub-receiving wireframe.

[0045] Alternatively, the first angle can be determined as:

[0046]

[0047] Where φ is the target detection aperture, θ i is the first angle, the value range of i is 1, 2…, n, and n is the number of at least one sub-receiving wireframe.

[0048] That is, the inherent detection aperture of the main receiving coil is equivalent to 43°, and the angle of the first angle is adjusted according to the target detection aperture of the antenna.

[0049] It should be understood that when determining the first angle in the present application, the inherent detection aperture of the main receiving coil may be equivalent to 45°, or the first angle θ may be determined by other methods according to actual conditions. i The relationship with the target detection aperture φ is not limited in this application.

[0050] In some implementations, at least one sub-receiving wireframe R X1The center point of any sub-receiving wireframe in the antenna does not coincide with the center point of the main receiving wireframe. When the antenna is arranged in this way, the observation area of ​​any sub-receiving wireframe is different, which can avoid calibration errors.

[0051] In some implementations, in the main receiving frame R X0 On the plane where the projection of the plane surrounded by any one of the at least one sub-receiving wireframes overlaps with the plane surrounded by the main receiving wireframe. Thus, the detection aperture of the antenna can be further reduced by using the signal data received by the sub-receiving wireframes.

[0052] In the antenna provided in the present application, by adjusting the normal direction angle between the sub-receiving wireframe and the main receiving wireframe, the electromagnetic detection data received by the sub-receiving wireframe can be used to correct the electromagnetic data received by the main receiving wireframe, thereby reducing the influence of the volume effect on the transient electromagnetic method.

[0053] Figure 2 is a schematic diagram of the structure of another antenna provided in an embodiment of the present application. In some implementations, the antenna further includes a transmitting wire frame T x , used to transmit electromagnetic detection signals, wherein the transmitting wire frame T x The normal to the main receiving wireframe R X0 That is, by determining the relationship between the transmitted electrical detection signal and the received electromagnetic signal, the signal received by the sub-receiving wireframe can correct the signal received by the main receiving wireframe, so that the antenna can achieve the purpose of target detection aperture. In addition, Figure 2 The sub-receiving wireframe R shown in X1 , R X2 and Figure 1 Neutron receiving wireframe R X1 The description is similar and will not be repeated here.

[0054] As a kind of launch wireframe T x With the main receiving wireframe R X0 The position relationship, such as Figure 2 As shown in (a), the transmitting wireframe Tx can be connected to the main receiving wireframe R X0 have the same shape and size, and the emission wireframe T x With the main receiving wireframe R X0 When the antenna is arranged in this way, the received electromagnetic response signal is most affected by the primary field, which is suitable for medium and long-distance target detection.

[0055] As another launch wireframe T x With the main receiving wireframe R X0 The position relationship, such as Figure 2 As shown in (b), the transmitting wireframe T xThe plane and the main receiving wireframe R X0 The planes are coplanar and the emission wireframe T x The center point of the main receiving wireframe R X0 The center point of the transmitting wireframe T x The area of ​​the enclosed area can be larger than the main receiving wireframe R X0 When the antenna is arranged in this way, the received electromagnetic response signal is moderately affected by the primary field, and the detection blind area near the target is small.

[0056] As another launch wireframe T x With the main receiving wireframe R X0 The position relationship, such as Figure 2 As shown in (c), the transmitting wireframe T x The plane and the main receiving wireframe R X0 The planes are parallel and have a spacing of d. When the antennas are arranged in this way, the electromagnetic signal is minimally affected by the primary field when it is collected, which is suitable for close-range target detection.

[0057] Figure 3 It is a schematic diagram of the structure of another antenna provided in an embodiment of the present application. It should be understood that the transmitting wire frame Tx and the main receiving wire frame R in the present application X0 The shape, size, number of turns, etc. of the sub-receiving wireframe are determined according to actual conditions, and this application does not limit this. For example, the wireframe can be as follows: Figure 3 In addition to the regular shapes such as triangles, rectangles, circles, etc. shown in (b), (c), and (d), the wireframe can also be an irregular shape such as a spiral.

[0058] In some implementations, such as Figure 3 As shown in (a), at least one sub-receiving wire frame in the antenna includes a first sub-receiving wire frame R X1 and the second sub-receiving wireframe R X2 Among them, the first sub-receiving wireframe R X1 The area enclosed by the second sub-receiving wireframe R has a first intersection with the area enclosed by the main receiving wireframe. X2 The enclosed area has a second intersection line with the area enclosed by the main receiving wire frame, and the first intersection line is parallel to the second intersection line. Thus, a survey line is arranged for a survey area, and the detection aperture is reduced in two directions in the survey line, reducing the influence of volume effect on transient electromagnetic method.

[0059] In some implementations, such as Figure 3 As shown in (c) or (d), at least one sub-receiving wireframe may include a third sub-receiving wireframe R X3 and the fourth sub-receiving wireframe R X4 Among them, the third sub-receiving wireframe R X3The area enclosed by the fourth sub-receiving wireframe R has a third intersection with the area enclosed by the main receiving wireframe. X4 The enclosed area has a fourth intersection line with the area enclosed by the main receiving wire frame, and the third intersection line intersects with the fourth intersection line. Thus, two measuring lines are arranged for one measuring area, the detection aperture is reduced in two directions, and the influence of volume effect on transient electromagnetic method is reduced.

[0060] In addition, the antennas can also be arranged as shown in (b), (c) or (d) according to actual conditions, and the measurement lines can be arranged in multiple directions. For example, as shown in (b), the sub-receiving wire frame R X1 , R X2 and R X3 , each sub-receiving wireframe corresponds to a different survey line. Or, as shown in Figure (c), set the sub-receiving wireframe R X1 , R X2 , R X3 and R X4 , where R X1 and R X3 Corresponding to the same measuring line, R X2 and R X4 Corresponding to the same survey line. Alternatively, as shown in (d) in the figure, set the sub-receiving wireframe R X1 , R X2 , R X3 , R X4 and R X5 , each sub-receiving wireframe corresponds to a different measuring line. In some implementations, the sub-receiving wireframes may be evenly arranged around the main wireframe.

[0061] The influence of the volume effect of the present application on the transient electromagnetic method is explained below with reference to specific expressions.

[0062] Figure 4 This is a schematic diagram of the principle of using an antenna to reduce the detection aperture provided by an embodiment of the present application. From the "smoke ring effect" of TEM, it can be seen that the effective coverage area of ​​the secondary magnetic field excited by the transmitting antenna can be equivalent to a cone that continues to extend outward over time. Taking the transmitting wireframe as a rectangular shape as an example, the base radius r(t) and axial distance d(t) of the cone are respectively:

[0063]

[0064]

[0065] Where t is the observation time, σ is the dielectric conductivity, μ0 is the magnetic permeability in vacuum, l is the side length of the rectangular wireframe, The cross-section of this conical detection area is as follows: Figure 4 As shown, the detection aperture of the transmitting antenna It can be expressed as:

[0066]

[0067] As time goes by, the bottom radius r(t) of the conical detection area will be much larger than the side length l of the wireframe. At this time, the emission wireframe can be regarded as a point source, and the size of l in the formula can be ignored. Then the detection aperture φ of the conventional planar emission wireframe is a fixed value:

[0068]

[0069] Combined with the reciprocity theorem of antennas, it can be seen that the conventional planar receiving wireframe has the same inherent detection aperture (φ′≈43°), and will receive electromagnetic response signals generated by geological bodies that are radially far away from the measuring point in the middle and late periods.

[0070] like Figure 4 As shown, using the application Figures 1 to 3 Any of the antennas shown can be used to connect the main receiving wire frame R x0 The normal direction of the detection direction is aligned with the detection direction, so that the main receiving wire frame R x0 Observe the overall induction field, and the collected electromagnetic response signal V0(t) comes from the geological body within the 43° inherent detection aperture. xi like Figure 4 The first angle is set to θ i , so as to collect the electromagnetic response signal V for the local area outside the induction field i (t). The alignment detection direction can be understood as the normal direction being the same as the detection direction. Alternatively, the main receiving wireframe R x0 It can also be arranged in other ways according to actual conditions, for example, the main receiving wire frame R x0 The normal direction may have a certain angle with the detection direction, and this application does not limit this.

[0071] As a correction method, the electromagnetic response signal V of the sub-receiving wireframe can be adjusted according to the angle relationship. i (t) is converted into a component in the detection direction and compared with the main receiving wireframe R x0 The difference between the electromagnetic response signal V0(t) and the induced electromotive force data V(t) after correction is taken as follows:

[0072]

[0073] where λ i For the sub-receiver wireframe R xiAfter the above signal correction process, the proportion of the electromagnetic response signal generated in the local area outside the induction field in the received data is significantly reduced, which can achieve the effect of reducing the detection aperture of the receiving end. x0 The inherent detection aperture (φ′≈43°) of this receiving antenna is xi The side where it is located has shrunk

[0074]

[0075] Where φ′ is the inherent detection aperture of the main receiving wireframe, θ i is the first angle, the value range of i is 1, 2..., n, and n is the number of at least one sub-receiving wireframe.

[0076] According to the above calculations, it can be determined that the use of the antenna of the present application can reduce the impact of the volume effect on the transient electromagnetic method, thereby achieving the purpose of improving the detection resolution.

[0077] In addition to the above antenna, the embodiments of the present application also provide a detection device and a detection system. The detection device provided in the embodiments of the present application may specifically refer to a transient electromagnetic detector or a geophysical detector, or other devices used for electromagnetic detection.

[0078] Figure 5 Schematic diagram of a detection device provided in an embodiment of the present application. Figure 5 As shown, the detection device may include Figures 1 to 3 The antenna, transmitter and receiver shown, wherein:

[0079] The transmitter 510 is electrically connected to the transmission wire frame Tx0. The transmitter is used to generate an excitation current. The excitation current is input into the transmission wire frame so that the transmission wire frame transmits an electromagnetic detection signal.

[0080] The transmitter 510 may specifically include a transmitting power supply, a control circuit, a driving circuit and a transmitting circuit. The transmitting power supply provides a stable voltage for the circuit system. When transmitting an electromagnetic detection signal, the control module drives the modulation current to be generated, and transmits the modulation current to the transmitting wire frame T through the transmitting circuit. x0 , thereby emitting an electromagnetic detection signal. The modulation current may be a pulse current or a bipolar square wave current with an adjustable duty cycle.

[0081] Receiver 520 and main receiving wireframe R x0 and at least one sub-receiving wire frame to obtain the electromotive force data of the electromagnetic response signal. x1 and R x2 situation.

[0082] The receiver 520 may specifically include a receiving module, an amplifying circuit, a filtering circuit, an analog / digital (A / D) conversion circuit, a storage circuit, and a correction circuit. The receiver may include a receiving wire frame R included in the slave antenna. x0 , R x1 , R x2 After receiving the data, it performs pre-processing such as time base correction, amplification, noise removal and A / D conversion to obtain the electromotive force data.

[0083] Among them, the correction circuit can be calculated according to the formula The electromagnetic response signal received from the antenna is processed.

[0084] In some implementations, the correction circuit in the receiver 520 includes multiple circuit channels. The multiple circuit channels are decoupled, and the wireframes in the main receiving wireframe and at least one sub-receiving wireframe correspond one-to-one to the circuit channels in the multiple circuit channels. In this case, each receiving wireframe included in the antenna independently transmits electromotive force data to the receiver.

[0085] In some implementations, the correction circuit in the receiver 520 includes a circuit channel, the main receiving wire frame and at least one sub-receiving wire frame are connected in series, and the main receiving wire frame and at least one sub-receiving wire frame correspond to one circuit channel. In this case, the physical connection between the receiving wire frames included in the antenna transmits the electromotive force to the receiver together. In addition to using independent wire frames, this series receiving antenna can also be formed by winding a wire, in which each part structure is equivalent to the main receiving wire frame R x0 and sub-receiver wireframe R x1 , R x2 , …, R xn .

[0086] In some implementations, the angle between the main receiving coil and the sub-receiving coil in the antenna is fixed. In this case, the winding direction of the main receiving wire frame and the winding direction of the sub-receiving wire frame can be set to be opposite, so that the physical connection of each receiving wire frame in the antenna can be directly used to correct the received signal. In addition, in some implementations, the size and number of turns of the sub-receiving wire frame can also be determined based on the posture information of the sub-receiving wire frame, so that the physical parameters of the wire frame can be used to implement weighted processing of the received signals of each sub-receiving wire frame.

[0087] In some implementations, the angle between the main receiving coil and the sub-receiving coil in the antenna is not fixed. Figure 5The detection device shown may also include a bracket for moving the wireframe in the antenna. The specific method of moving the wireframe may also include rotating the wireframe. At this time, the receiver may also include a compass for recording the attitude information of the wireframe included in the antenna. In this case, a corresponding correction circuit may be designed to correctly process the electromagnetic response signals received by the main receiving wireframe Rx0 and the sub-receiving wireframe Rxi.

[0088] In the above two implementations, the posture information of the sub-receiving wireframe is mainly used to confirm the angle between the sub-receiving wireframe Rxi and the main receiving wireframe Rx0. For example, the posture information may specifically refer to the angle between the sub-receiving wireframe Rxi and the normal direction of the main receiving wireframe Rx0, or the equivalent receiving area of ​​the sub-receiving wireframe Rxi in the plane where the main receiving wireframe Rx0 is located, etc., and this application does not limit this.

[0089] As an implementation method for determining the size and number of turns of the sub-receiving wireframe according to the posture information of the sub-receiving wireframe, for example, the angle between the normal direction of the sub-receiving wireframe and the normal direction of the main receiving wireframe is θ i , the area of ​​the sub-receiving wireframe is S i , the equivalent receiving area of ​​the sub-receiving wireframe can be understood as λ i = cosθ i S i , that is, θ i When it is 0 degrees, the equivalent receiving area of ​​the sub-receiving wireframe is the largest, θ i When the angle is 90 degrees, the equivalent receiving area of ​​the sub-receiving wireframe is the smallest. According to the above formula Adjust the electromotive force. When the equivalent receiving area of ​​the sub-receiving wireframe in the plane where the main receiving wireframe is located is small, the size and number of turns of the sub-receiving wireframe can be increased accordingly, thereby increasing the resistance of the sub-receiving wireframe, reducing the electromotive force of the sub-receiving wireframe, and gaining the electromagnetic response signal received by the sub-receiving wireframe. When the equivalent receiving area of ​​the plane where the main receiving wireframe is located is large, the size and number of turns of the sub-receiving wireframe can be reduced accordingly, thereby reducing the resistance of the sub-receiving wireframe, increasing the electromotive force of the sub-receiving wireframe, and gaining the electromagnetic response signal received by the sub-receiving wireframe.

[0090] Figure 6 Schematic diagram of a correction circuit provided in an embodiment of the present application. Figure 6 As shown, when the correction circuit 600 includes multiple circuit channels, a difference and sum module can be set in the correction circuit 600, so that the correction circuit 600 can be used to compare the electromotive force data of the circuit channel corresponding to the main receiving wire frame with the electromotive force data V1(t), ..., V0(t) of the circuit channel corresponding to at least one sub-receiving wire frame. iThus, when the angle between the main receiving coil and the sub receiving coil is not fixed, the correction circuit is used to implement correction processing on the received signal.

[0091] In some implementations, a gain module 610 may also be provided in the correction circuit. The gain module is specifically located in one or more circuit channels corresponding to the sub-receiving wireframe. The gain module is used to perform intensity gain on the current in the circuit channel corresponding to the sub-receiving wireframe according to the posture information of the sub-receiving wireframe. The posture information may be obtained from a compass. The compass is electrically connected to the bracket, and the compass is electrically connected to the correction circuit 610. The compass is used to record the posture information of the wireframe included in the antenna and transmit the posture information to the correction circuit 610. In some implementations, the gain module may perform intensity gain on the current in the circuit channel corresponding to the sub-receiving wireframe according to the effective receiving area of ​​the sub-receiving wireframe. Thus, the weighted processing of the received signals of each sub-receiving wireframe is implemented by using the gain module in the circuit.

[0092] In some implementations, a control switch may be provided in a circuit path included in the correction circuit 600 to specifically control each circuit path.

[0093] The specific form of the correction circuit and each module therein is determined according to actual conditions. For example, the correction circuit can be in the form of a hardware product, or it can also be in the form of a software product, and this application does not impose any restrictions on this.

[0094] Figure 7 Schematic diagram of a detection system provided in an embodiment of the present application. Figure 7 As shown, the detection system may include Figure 5 The detection device and host computer 730 shown, wherein:

[0095] The host computer 730 is used to control the transmitter 710 and the receiver 720 in the detection device. In addition, the host computer is also used to obtain electromotive force data from the receiver 720 and process the electromotive force data to obtain the resistivity of the detection target.

[0096] In some implementations, software may be provided in the host computer 710 to specifically control the control circuit, correction circuit, etc. in the detection device, or software may be used to replace part or all of the functions of the control circuit and correction circuit.

[0097] Among them, the host computer described in the embodiment of the present application may specifically refer to a computer or other interactive device that runs operation instructions.

[0098] Figure 8 : is a schematic diagram of an apparent resistivity profile result provided in an embodiment of the present application. Figure 8(a) corresponds to the resistivity profile result obtained by directly processing the electromagnetic response signal received by the main receiving coil. Figure 8 (b) corresponds to the resistivity profile result directly obtained by using the electromagnetic response signal received by the antenna of the present application. Wherein, the resistivity is represented by ρ. Figure 8 (a) and Figure 8 In (b), it can be seen that the resolution of the inversion results is significantly improved.

[0099] The following describes the application scenarios in which the antenna and detection device of the present application are applicable.

[0100] Fig. 9 It is a schematic diagram of an application scenario applicable to an antenna and a detection device provided in an embodiment of the present application.

[0101] like Fig. 9 As shown in (a), the antenna, detection device and detection system of the present application can be applied to various ground detection work, such as exploration of metal mines and oil and gas fields, site selection of bridges and buildings, quality investigation of dams and detection of underground ancient buildings. These application scenarios have high requirements on the longitudinal resolution and detection depth of TEM detection. Usually, a single-turn coil with a side length greater than 50m is required as the transmitting antenna and the distance between the measuring points is increased accordingly. At this time, the conventional receiving antenna can only obtain detection results with low lateral resolution. By using the antenna, detection device or detection system of the present application, the receiving wireframe R in the antenna can be set accordingly. x and the emission wireframe T x , the main receiving wire frame and the transmitting wire frame T x The center loop is laid horizontally on the ground surface, and multiple sub-receiving wireframes are arranged at a certain angle to the ground, so that the detection aperture of the receiving end can be reduced along the survey line direction. This supports the use of large-size transmitting antennas while encrypting the measurement points, and realizes deep and high-resolution ground TEM detection.

[0102] like Fig. 9 As shown in (b), the antenna, detection device and detection system of the present application can be applied to underground detection. For example, in underground excavation projects such as mine tunnels, traffic tunnels and water diversion tunnels, advanced geological forecasting work can be carried out for water hazards. Limited by such underground construction environments, multi-turn wire frames with a side length of less than 3m are usually used as transceiver antennas for TEM detection, and only a small number of measuring points and angles can be set at the excavation surface to form a fan-shaped observation system. However, by using the antenna, detection device or detection system of the present application, the receiving wire frame R in the antenna can be set accordingly. x and the emission wireframe T x , reducing the detection aperture in the horizontal and vertical directions, thereby encrypting the measurement points and angles when the working space is limited, and realizing high-resolution underground TEM detection.

[0103] like Fig. 9 As shown in (c), the antenna, detection device and detection system of the present application can be applied to the field of aerial detection. It is often difficult to carry out ground TEM detection under complex terrain conditions such as forests, deserts, Gobi and mountains. Using helicopters or drones as carrier platforms for aerial TEM detection can significantly improve work efficiency. As a setting method for aerial detection, the antenna of the present application can be suspended at a certain distance below the aircraft in a flexible connection manner, and other processing devices can be set in the aircraft cabin. Aerial TEM detection is a dynamic observation process. According to the technical solution of the present application, the receiving wireframe R in the antenna can be set accordingly. x and the emission wireframe T x , after reducing the detection aperture, the measurement points can be encrypted while keeping the flight path unchanged, further improving the lateral resolution of the detection results.

[0104] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0105] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0106] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or detection connection shown or discussed can be through some interfaces, indirect coupling or detection connection of devices or units, which can be electrical, mechanical or other forms.

[0107] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0108] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0109] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage media include: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROM), random access memories (RAM), magnetic disks or optical disks.

[0110] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An antenna, characterized in that: include: A main receiving wireframe and at least one sub-receiving wireframe, for receiving an electromagnetic response signal; The normal direction of any one of the at least one sub-receiving wireframes has a first angle greater than 0 degrees with the normal direction of the main receiving wireframe, and the degree of the first angle is determined according to the target detection aperture of the antenna.

2. The antenna according to claim 1, characterized in that The first angle is also determined according to the inherent detection aperture of the main receiving wireframe.

3. The antenna according to claim 1 or 2, characterized in that: in: When the target detection aperture is greater than 0° and less than 43°, the relationship between the first angle and the target detection aperture satisfies θ i =φ+43°; When the target detection aperture is greater than or equal to 43° and less than 90°, the first angle satisfies 86°≤θ i <90°; Where, φ is the target detection aperture, θ i is the first angle, the value range of i is 1, 2…, N, and N is the number of the at least one sub-receiving wireframe.

4. The antenna according to claim 1 or 2, characterized in that: in: When the target detection aperture is greater than 0° and smaller than the target detection aperture, the relationship between the first angle and the target detection aperture satisfies θ i =φ+φ′; When the target detection aperture is greater than or equal to the target detection aperture and less than 90°, the first angle satisfies 2φ′≤θ i <90°; Where, φ is the target detection aperture, θ i is the first angle, the value range of i is 1, 2…, N, and N is the number of the at least one sub-receiving wireframe.

5. The antenna according to any one of claims 1 to 4, characterized in that: The center points of any sub-receiving wireframe in the at least one sub-receiving wireframe do not overlap.

6. The antenna according to any one of claims 1 to 5, characterized in that: On the plane where the main receiving wireframe is located, a projection of an area enclosed by any one of the at least one sub-receiving wireframes has an overlapping portion with an area enclosed by the main receiving wireframe.

7. The antenna according to any one of claims 1 to 6, characterized in that: The at least one sub-receiving wireframe includes a first sub-receiving wireframe and a second sub-receiving wireframe, wherein an area enclosed by the first sub-receiving wireframe has a first intersection with an area enclosed by the main receiving wireframe, and an area enclosed by the second sub-receiving wireframe has a second intersection with an area enclosed by the main receiving wireframe, and the first intersection is parallel to the second intersection.

8. The antenna according to any one of claims 1 to 6, characterized in that: The at least one sub-receiving wireframe includes a third sub-receiving wireframe and a fourth sub-receiving wireframe, wherein an area enclosed by the third sub-receiving wireframe has a third intersection with an area enclosed by the main receiving wireframe, an area enclosed by the fourth sub-receiving wireframe has a fourth intersection with an area enclosed by the main receiving wireframe, and the third intersection intersects with the fourth intersection.

9. The antenna according to any one of claims 1 to 8, characterized in that The antenna further comprises a transmitting wire frame for transmitting an electromagnetic detection signal, wherein a normal line of the transmitting wire frame coincides with a normal line of the main receiving wire frame.

10. The antenna according to claim 9, characterized in that: in: The transmitting wireframe has the same shape and size as the main receiving wireframe, and the transmitting wireframe is in contact with the main receiving wireframe; or The plane where the transmitting wireframe is located is coplanar with the plane where the main receiving wireframe is located, and the center point of the transmitting wireframe coincides with the center point of the main receiving wireframe; or The plane where the transmitting wire frame is located is parallel to the plane where the main receiving wire frame is located and there is a gap between them.

11. A detection device, characterized in that: The invention comprises a transmitter, a receiver and an antenna as claimed in claim 9 or 10, wherein: The transmitter is electrically connected to the transmitting wire frame, and the transmitter is used to generate an excitation current, and the excitation current is input into the transmitting wire frame so that the transmitting wire frame transmits the electromagnetic detection signal; The receiver is electrically connected to the main receiving wire frame and at least one sub-receiving wire frame to obtain electromotive force data of the electromagnetic response signal.

12. The detection device according to claim 11, characterized in that: The receiver comprises a correction circuit, wherein: The correction circuit includes a plurality of circuit channels, the plurality of circuit channels are decoupled from each other, and the wire frames in the main receiving wire frame and at least one sub-receiving wire frame correspond one-to-one to the circuit channels in the plurality of circuit channels.

13. The detection device according to claim 12, characterized in that: The correction circuit is used to subtract the electromotive force data of the circuit channel corresponding to the main receiving wire frame from the electromotive force data of the circuit channel corresponding to the at least one sub-receiving wire frame.

14. The detection device according to claim 11, characterized in that: The receiver comprises a correction circuit, wherein: The correction circuit includes a circuit path, the main receiving wire frame and the at least one sub-receiving wire frame are connected in series, and the main receiving wire frame and the at least one sub-receiving wire frame correspond to the circuit path.

15. The detection device according to claim 14, characterized in that: The winding direction of the main receiving wire frame is opposite to the winding direction of the sub-receiving wire frame.

16. The detection device according to any one of claims 11 to 15, characterized in that: The detection device also includes a bracket, wherein: The bracket is used to move the wire frame in the antenna; The receiver further comprises a compass, the bracket is electrically connected to the compass, and the compass is electrically connected to the correction circuit, the compass is used to record the attitude information of the wire frame included in the antenna, and transmit the attitude information to the correction circuit; The correction circuit further includes a gain module, which is disposed in the circuit channel and is used for performing intensity gain on the current in the circuit channel corresponding to the sub-receiving wireframe according to the posture information of the sub-receiving wireframe.

17. The detection device according to any one of claims 11 to 15, characterized in that: The size and number of turns of the sub-receiving wireframe are determined according to the posture information of the sub-receiving wireframe.

18. A detection system, comprising a detection device as described in any one of claims 11 to 16 and a host computer, wherein the host computer is used to control the transmitter and the receiver, and the host computer is also used to obtain the electromotive force data and process the electromotive force data to obtain the resistivity of the detection target.

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