A system and method for controlled-source electromagnetic exploration is based on staggered frequency excitation of crossed sources. Different high-order pseudo-random signals are transmitted using two sources, respectively, each set of high-order pseudo-random signals may contain sufficient frequencies within a same complete frequency range, exploration frequencies of the two sets of signals are completely staggered, simultaneous transmission by the two field sources is implemented, and different polarization modes do not affect each other and are separated from each other. Moreover, different measuring line directions at a receiving terminal can be observed simultaneously, and each measuring point has two polarization directions, thus greatly improving the exploration efficiency and the data volume.

A system and method for controlled-source electromagnetic exploration is based on staggered frequency excitation of crossed sources. Different high-order pseudo-random signals are transmitted using two sources, respectively, each set of high-order pseudo-random signals may contain sufficient frequencies within a same complete frequency range, exploration frequencies of the two sets of signals are completely staggered, simultaneous transmission by the two field sources is implemented, and different polarization modes do not affect each other and are separated from each other. Moreover, different measuring line directions at a receiving terminal can be observed simultaneously, and each measuring point has two polarization directions, thus greatly improving the exploration efficiency and the data volume.

A system and techniques for detecting near-subsurface voids in the earth use a controlled source electromagnetic transmitter and a plurality of controlled source electromagnetic receivers. Signals received by the plurality of controlled source electromagnetic receivers corresponding to signals generated by the controlled source electromagnetic transmitter are analyzed. Bi-static doublets detected in the received signals are used to identify the location of the near-subsurface voids.

Disclosed are methods and systems for conditioning electrodes while deployed in the sea with a marine electromagnetic survey system. An embodiment of the method may comprise deploying electrodes in seawater during a marine electromagnetic survey. The method further may comprise coupling at least one of the electrodes to a controllable current/voltage source while the electrodes are deployed in the seawater. The method further may comprise sending a first conditioning signal from the controllable current/voltage source to the at least one of the electrodes coupled to the controllable current/voltage source.

A device and method for measuring spectrum parameters of a formation outcrop and a rock mass are provided. An excitation signal is generated by a direct digital synthesis (DDS) module of a signal transmission portion. A constant voltage mode or a constant current mode is adopted for observation. After the signal passes through a constant voltage/constant current module, a constant high-voltage signal source or a current source signal with constant current output is formed and output to ground through grounding electrodes A and B to establish a stable observation signal field source. Geoelectric response information under the excitation of each frequency signal is acquired by a signal receiving portion through grounding electrodes M and N, processed and send out to a microcontroller unit (MCU) for display and storage. The spectrum parameters at different depths are observed by adjusting geometric dimensions of AB and MN.

A computer implemented method that enables detection and mitigation of drilling hazards is described. The method includes determining time-domain electromagnetic parameters and obtaining data at multiple heights by at least one unmanned aerial vehicle equipped with at least one receiver as a time-domain electromagnetic transmitter emits electromagnetic radiation based on the time-domain electromagnetic parameters. The method also includes fusing the obtained data to generate a subsurface model.

Provided is a method for positioning and predicting concealed orebody based on parallel double-tunnel transient electromagnetic exploration, and belongs to the applied geophysics exploration technology. The method can locate and predict concealed orebodies with low resistivity around the tunnel in a full spatial domain based on a parallel double-tunnel transient electromagnetic method. The implementation of the method mainly includes measuring an electrical parameter, observing a tunnel transient electromagnet, calculating an apparent resistivity, determining an upper limit of an apparent resistivity abnormity, delineating the apparent resistivity abnormity and positioning and predicting concealed orebodies. The method can effectively solve the double-solution problem of positioning concealed orebodies in the full spatial domain of the tunnel.

This method can be used to locate or identify an object in an electrically conductive medium with a detection system that comprises n electrodes in direct electrical contact with the conductive medium. The n electrodes can be placed in at least three different states: transmitting, receiving, disconnected. Before a series of measurements, the operating point of the detection system is determined according to a given a priori setpoint, or a previous configuration of the system, or a previous measurement result of one of the electrodes, by the configuration of the state of each of the electrodes, the frequency of a sinusoidal component of an electrical signal transmitted by one of the transmitting electrodes, or the amplitude of the electrical signal transmitted by one of the electrodes configured in the transmitting or receiving state.