Abstract: The present disclosure provides an apparent resistivity-depth section generating method for short-offset electromagnetic exploration, including: determining, in field zones divided quantitatively based on the induction number, positions of a recording point for each of observation points and frequencies or a time window thereof; and taking determined positions of the recording point as the assignment point for the observation point and the frequencies or the time window thereof, where one survey line of an axial configuration generates one apparent resistivity-depth section along the survey line; and one survey line of an equatorial configuration typically generates one apparent resistivity-depth section along the survey line, and apparent resistivity-depth sections along connecting lines from the observation points to the source which are the same as observation points in the number.

Abstract: Disclosed is an exploration method and system for pegmatite veins. The exploration method includes: three grounding electrodes are arranged at each observation point in a target area where pegmatite veins are located, and collecting electric field differences between two groups of grounding electrodes; drawing a multi-channel map, based on positions of the grounding electrodes, according to the electric field differences; obtaining resistivity variation characteristics of pegmatite veins according to the transverse variation of multi-channel map, and determining locations and lithologic characteristics of pegmatite veins according to the resistivity variation characteristics. Through functional modules with different functions, an exploration system is formed to realize the exploration method mentioned in the application.

Abstract: Disclosed is an exploration method and system for pegmatite veins. The exploration method includes: three grounding electrodes are arranged at each observation point in a target area where pegmatite veins are located, and collecting electric field differences between two groups of grounding electrodes; drawing a multi-channel map, based on positions of the grounding electrodes, according to the electric field differences; obtaining resistivity variation characteristics of pegmatite veins according to the transverse variation of multi-channel map, and determining locations and lithologic characteristics of pegmatite veins according to the resistivity variation characteristics. Through functional modules with different functions, an exploration system is formed to realize the exploration method mentioned in the application.

Abstract: This application provides an adaptive damping magnetic field sensor, including: a receiving coil, an adaptive damping matching resistance circuit, and an amplifying circuit; where the receiving coil is used for receiving an earth response signal generated by the earth under excitation of an emission source, and generating an induced voltage; the adaptive damping matching resistance circuit is used for receiving the induced voltage generated by the receiving coil and automatically matching a damping resistance value to obtain a near-source broadband observation signal; and the amplifying circuit is used for amplifying the observation signal with a constant gain and outputting a sensor output signal. This application carries out automatic matching control on the damping resistance value through the adaptive damping matching resistance circuit, thereby ensuring that the sensor can stably and reliably implement fine observation of an earth response under near-source, broadband and complex scene conditions.

Abstract: Disclosed are a multi-line source ground-borehole transient electromagnetic detection method and a multi-line source ground-borehole transient electromagnetic detection device. The method includes following steps: S1, constructing a multi-line source ground-borehole transient electromagnetic forward model; S2, obtaining multi-line source ground-borehole transient electromagnetic responses of an underground target layer by the multi-line source ground-borehole transient electromagnetic forward model; and S3, recognizing the underground target layer according to electromagnetic diffusion characteristics of the multi-line source ground-borehole transient electromagnetic responses. A resolution and a detection capability of the underground target by a ground-borehole transient electromagnetic method is greatly improved by adopting technical schemes.

Abstract: Embodiments of a method for measurement of electromagnetic field strength at a point of interest in a coverage area of a 2-dimensional (2D) active antenna system (AAS). The 2D AAS transmits with a load factor of 100 percent. The 2D AAS sweeps a predefined range of azimuth and elevation angles, and azimuth and elevation directions which yield highest EMF at the point of interest are determined. First beamforming weights are determined based on the azimuth and elevation directions and the 2D AAS caused to apply the first beamforming weights. The 2D AAS sweeps a co-phasing angle from 0 to 360 degrees, and a co-phasing angle which yields highest EMF is determined. Second beamforming weights are determined based on azimuth and elevation directions and the co-phasing angle, and the 2D AAS caused to apply the second beamforming weights. The EMF strength at the point of interest is measured.

Abstract: A method of solving closed form exact solution for the field generated by a finite-length harmonic linear current source in a whole space. The vector magnetic potential formula of the finite-length harmonic linear current source containing a source point position vector is listed, the uniform current is subjected to cosine processing, and the current in the vector magnetic potential formula of the harmonic linear current source is expressed by a cosine function. The vector magnetic potential formula can be subjected to quadrature by an elementary function to obtain the closed form exact solution for the field generated by the finite-length harmonic linear current source in whole space. The cosine expression of the linear current source can better reflect the fundamental attributes of the electric dipole and harmonic current of linear current source in the conductive whole space. The obtained closed form exact solution is applicable in the all zone.

Abstract: A method and system for electromagnetic method (EM) signal detection based on an onshore sparker source, the method including: arranging an EM signal detection system near a sparker source; releasing, by the sparker source, an electromagnetic pulse concomitantly in a discharge and mechanical energy output process; observing an electromagnetic response generated by the earth under the excitation of the electromagnetic pulse by means of the EM signal detection system for extracting distribution information of geo-electrical parameters; when the sparker source moves, moving the electromagnetic method signal detection system to a new position along with the sparker source while keeping their positions relative to each other unchanged; and repeating the above process after the movement is completed. According to the technical solution of the present invention, fine electromagnetic detection results can be obtained while seismic detection is carried out.

Abstract: A method of solving closed form exact solution for the field generated by a finite-length harmonic linear current source in a whole space. The vector magnetic potential formula of the finite-length harmonic linear current source containing a source point position vector is listed, the uniform current is subjected to cosine processing, and the current in the vector magnetic potential formula of the harmonic linear current source is expressed by a cosine function. The vector magnetic potential formula can be subjected to quadrature by an elementary function to obtain the closed form exact solution for the field generated by the finite-length harmonic linear current source in whole space. The cosine expression of the linear current source can better reflect the fundamental attributes of the electric dipole and harmonic current of linear current source in the conductive whole space. The obtained closed form exact solution is applicable in the all zone.

Abstract: The disclosure pertains to the field of exploration based on electromagnetic method, and in particular relates to a method and device for surface-borehole transient electromagnetic detection, aiming at solving the problem that the loop source device cannot effectively detect the high-resistance layer. The device according to the disclosure includes grounded conductor wires as emission sources and underground receiving devices as receiving sources; wherein the grounded conductor wires are arranged on the ground; an existing borehole on the ground or an existing underground roadway is used, and receiving probes are arranged point by point in the borehole direction or in the horizontal direction of the roadway; the grounded conductor wires are composed of three sets of grounded conductor wires, wherein two sets of the grounded conductor wires are arranged in parallel with each other and perpendicular to the third set of the grounded conductor wires.

Abstract: Disclosed is a method for extracting IP information in a TEM response of a grounded-wire source, comprising the following steps: 1) obtaining subsurface resistivity through inversion of a vertical magnetic field less influenced by an IP effect; 2) obtaining an electric field response not influenced by the IP effect based on forward modeling of the obtained underground electrical structure; 3) removing the influence of the IP effect on an observed response to obtain a pure IP response; and 4) inverting the obtained IP response to obtain IP information of polarizability, a frequency dependence, and a time constant. The method of the present invention provides a new idea for further extracting IP information in a TEM response.

Abstract: A system for emulating a plurality of wireless communication channels is provided. The system includes a plurality of elevation steering devices configured to modify at least one elevation characteristic of a plurality of signals and a plurality of combiners. Each combiner is configured to combine at least two signals of the plurality of signals to output a combined signal. The plurality of combiners output a plurality of combined signals. The system includes a plurality of azimuth steering devices configured to modify at least one azimuth characteristic of the plurality of combined signals. The plurality of elevation steering devices and the plurality of azimuth steering devices emulate the plurality of wireless communication channels.

Abstract: The present disclosure discloses a distributed airborne electromagnetic detection system, and relates to an airborne electromagnetic detection technology. The distributed airborne electromagnetic detection system comprises at least one transmitting system, at least one receiving system, at least one trunk module, and an earth station, and also a plurality of Unmanned Aerial Vehicles (UAVs) for carrying the transmitting system, the receiving system, and the trunk module. The distributed airborne electromagnetic detection system does not require high performance or high economical efficiency for a single UAV; under precise synchronous flight conditions, the distance between a type I UAV and a transmitting loop structure can be greatly reduced, thereby significantly reducing the length of unwanted transmitting cable; and in addition, due to the better low-altitude low-speed performance of UAVs, the traveling speed of the entire system can be further reduced, thus obtaining higher quality data.

Abstract: A system for emulating a plurality of wireless communication channels is provided. The system includes a plurality of elevation steering devices configured to modify at least one elevation characteristic of a plurality of signals and a plurality of combiners. Each combiner is configured to combine at least two signals of the plurality of signals to output a combined signal. The plurality of combiners output a plurality of combined signals. The system includes a plurality of azimuth steering devices configured to modify at least one azimuth characteristic of the plurality of combined signals. The plurality of elevation steering devices and the plurality of azimuth steering devices emulate the plurality of wireless communication channels.

Abstract: The disclosure pertains to the field of electromagnetic exploration, and in particular relates to a device and method for ground source transient electromagnetic near-field detection and related device, with the purpose of solving the problems that the method for loop source transient electromagnetic detection has a relatively small detection depth and weak signals. The device of the disclosure includes an excitation source emitting device and a receiving device for signal detection. The excitation source emitting device includes an emission source, the emission source is a grounded conductor wire; the grounded conductor wire is used to convert a bipolar pulsed current into an electromagnetic field to be emitted underground; and the receiving device is configured for detecting a magnetic field and/or electric field signal in a survey line segment of an observation range of the grounded conductor wire using the method of areal sideline scanning survey.

Abstract: A method and system for electromagnetic method (EM) signal detection based on an onshore sparker source, the method including: arranging an EM signal detection system near a sparker source; releasing, by the sparker source, an electromagnetic pulse concomitantly in a discharge and mechanical energy output process; observing an electromagnetic response generated by the earth under the excitation of the electromagnetic pulse by means of the EM signal detection system for extracting distribution information of geo-electrical parameters; when the sparker source moves, moving the electromagnetic method signal detection system to a new position along with the sparker source while keeping their positions relative to each other unchanged; and repeating the above process after the movement is completed. According to the technical solution of the present invention, fine electromagnetic detection results can be obtained while seismic detection is carried out.

Abstract: Disclosed in the present invention is a multi-mode data observation method based on unmanned aerial vehicle formation for semi-airborne electromagnetic surveying. The method includes four basic formation modes: a ZX formation mode for obtaining the Z component of the response field with a high signal-to-noise ratio and the X direction gradient data of the Z component of the response field in different scales; a ZZ formation mode for obtaining the Z direction gradient data of the Z component of the response field in different scales; an XX formation mode for obtaining the X component of the response field with a high signal-to-noise ratio and the X direction gradient data of the X component of the response field in different scales; an XZ formation mode for obtaining the Z direction gradient data of the X component of the response field in different scales.

Abstract: Disclosed in the present invention is a multi-mode data observation method based on unmanned aerial vehicle formation for semi-airborne electromagnetic surveying. The method includes four basic formation modes: a ZX formation mode for obtaining the Z component of the response field with a high signal-to-noise ratio and the X direction gradient data of the Z component of the response field in different scales; a ZZ formation mode for obtaining the Z direction gradient data of the Z component of the response field in different scales; an XX formation mode for obtaining the X component of the response field with a high signal-to-noise ratio and the X direction gradient data of the X component of the response field in different scales; an XZ formation mode for obtaining the Z direction gradient data of the X component of the response field in different scales.