Abstract: A multi-sensor electromagnetic (EM) system and method for measuring gradients of EM signals. The multi-sensor EM system includes a frame; a transmitter device attached to the frame and configured to generate a primary EM field; a receiver device attached to the frame and configured to record a secondary EM field generated by the earth after being excited by the primary EM field; and a gradient sensor device attached to the frame and configured to record a gradient of the secondary EM field.

Abstract: A multi-sensor electromagnetic (EM) system and method for measuring gradients of EM signals. The multi-sensor EM system includes a frame; a transmitter device attached to the frame and configured to generate a primary EM field; a receiver device attached to the frame and configured to record a secondary EM field generated by the earth after being excited by the primary EM field; and a gradient sensor device attached to the frame and configured to record a gradient of the secondary EM field.

Abstract: A multi-sensor electromagnetic (EM) system and method for measuring gradients of EM signals. The multi-sensor EM system includes a frame; a transmitter device attached to the frame and configured to generate a primary EM field; a receiver device attached to the frame and configured to record a secondary EM field generated by the earth after being excited by the primary EM field; and a gradient sensor device attached to the frame and configured to record a gradient of the secondary EM field.

Abstract: An electromagnetic (EM) receiver system for measuring EM signals. The EM receiver system includes a survey EM transmitter for generating survey EM signals within a first frequency range; a calibration EM transmitter for generating a calibration signal; a receiver section, including a receiver housing and a receiver, that measures both the survey EM signals and the calibration signal; and a calibration device connected to the calibration EM transmitter and to the receiver, the calibration device configured to control a frequency and waveform of the calibration signal. The calibration device is further configured to calculate a response function of the receiver, based on the calibration signal.

Abstract: A multi-sensor electromagnetic (EM) system and method for measuring gradients of EM signals. The multi-sensor EM system includes a frame; a transmitter device attached to the frame and configured to generate a primary EM field; a receiver device attached to the frame and configured to record a secondary EM field generated by the earth after being excited by the primary EM field; and a gradient sensor device attached to the frame and configured to record a gradient of the secondary EM field.

Abstract: A multi-sensor electromagnetic (EM) system and method for measuring gradients of EM signals. The multi-sensor EM system includes a frame; a transmitter device attached to the frame and configured to generate a primary EM field; a receiver device attached to the frame and configured to record a secondary EM field generated by the earth after being excited by the primary EM field; and a gradient sensor device attached to the frame and configured to record a gradient of the secondary EM field.

Abstract: An electromagnetic geophysical exploration system includes transmitter-receiver pairs configured to transmit waveforms and sense signals in different frequency bands. A controller directs the transmitters of the transmitter-receiver pairs to transmit the waveforms at different moments while the electromagnetic geophysical exploration system is flown over a subsurface formation. The signals sensed by the receivers enable geophysical exploration of the subsurface formation.

Abstract: An electromagnetic (EM) receiver system for measuring EM signals. The EM receiver system includes a platform; a coil for measuring EM signals; and first to third suspension mechanisms located between the platform and the coil so that the coil oscillates relative to the platform, and the first to third suspension mechanisms attenuate motion induced noise introduced by towing the receiver system above ground.

Abstract: An electromagnetic (EM) receiver system for measuring EM signals. The EM receiver system includes a survey EM transmitter for generating survey EM signals within a first frequency range; a calibration EM transmitter for generating a calibration signal; a receiver section, including a receiver housing and a receiver, that measures both the survey EM signals and the calibration signal; and a calibration device connected to the calibration EM transmitter and to the receiver, the calibration device configured to control a frequency and waveform of the calibration signal. The calibration device is further configured to calculate a response function of the receiver, based on the calibration signal.

Abstract: An electromagnetic (EM) receiver system for measuring EM signals. The EM receiver system includes a platform; a coil for measuring EM signals; and first to third suspension mechanisms located between the platform and the coil so that the coil oscillates relative to the platform, and the first to third suspension mechanisms attenuate motion induced noise introduced by towing the receiver system above ground.

Abstract: A composite electromagnetic (EM) system and method for measuring naturally occurring magnetic fields and controlled magnetic fields. The composite EM system includes a housing, an audio-magnetotelluric (AMT) system attached to the housing and measuring natural magnetic fields generated by earth, a frequency-domain EM (FDEM) system attached to the housing and measuring controlled magnetic fields generated by a controlled source, and a position and orientation (POS) system attached to the housing and configured to calculate an orientation and a position of the AMT system and housing relative to the earth. The housing is configured to be attached to an aircraft for being airborne while measuring the natural magnetic fields and the controlled magnetic fields.

Abstract: An electromagnetic (EM) receiver system for measuring EM signals. The EM receiver system includes a survey EM transmitter for generating survey EM signals within a first frequency range; a tracking EM transmitter for generating tracking signals within a second frequency range; and a receiver section including a receiver that measures both the survey EM signals and the tracking signals.

Abstract: An electromagnetic (EM) receiver system for measuring EM signals. The EM receiver system includes a platform; a coil for measuring EM signals; and first to third suspension mechanisms located between the platform and the coil so that the coil oscillates relative to the platform, and the first to third suspension mechanisms attenuate motion induced noise introduced by towing the receiver system above ground.

Abstract: An electromagnetic geophysical exploration system includes a first transmitter-receiver pair that includes a first transmitter configured to transmit a first waveform in a first spectrum and a first receiver configured to sense signals in the first spectrum; and a second transmitter-receiver pair that includes a second transmitter configured to transmit a second waveform in a second spectrum, the second spectrum having a frequency higher than a frequency of the first spectrum, and a second receiver configured to sense signals in the second spectrum; and a control portion. The control portion controls the first transmitter to transmit the first waveform with a first given strength or shape in the first spectrum, and controls the second transmitter to transmit the second waveform with a second given strength or shape in the second spectrum, after a specified time delay.

Abstract: An electromagnetic geophysical exploration system includes a first transmitter configured to transmit a first waveform in a first spectrum, a first receiver configured to sense signals in the first spectrum, a second transmitter configured to transmit a second waveform in a second spectrum, the second spectrum having a frequency higher than a frequency of the first spectrum, a second receiver configured to sense signals in the second spectrum, the second receiver configured to be minimum-coupled to the second transmitter, wherein a transmitter coil of the second transmitter is disposed between an inner receiver coil and an outer receiver coil of the second receiver, and the inner receiver coil and the outer receiver coil of the second receiver surround the transmitter coil of the second transmitter, and a control portion configured to control the first transmitter and the second transmitter.

Abstract: An electromagnetic (EM) receiver system for measuring EM signals. The EM receiver system includes a platform; a coil for measuring EM signals; and first to third suspension mechanisms located between the platform and the coil so that the coil oscillates relative to the platform, and the first to third suspension mechanisms attenuate motion induced noise introduced by towing the receiver system above ground.

Abstract: An electromagnetic (EM) receiver system for measuring EM signals. The EM receiver system includes a survey EM transmitter for generating survey EM signals within a first frequency range; a tracking EM transmitter for generating tracking signals within a second frequency range; and a receiver section including a receiver that measures both the survey EM signals and the tracking signals.

Abstract: An electromagnetic (EM) receiver system for measuring EM signals. The EM receiver system includes a platform; a coil for measuring EM signals; and first to third suspension mechanisms located between the platform and the coil so that the coil oscillates relative to the platform, and the first to third suspension mechanisms attenuate motion induced noise introduced by towing the receiver system above ground.

Abstract: A method and system for active cancellation of transient signals and dynamic loop configuration for geophysical exploration is disclosed. The method includes controlling a transmitter to transmit a waveform in a frequency spectrum during an on-time. The transmitter includes a plurality of turns of wire. The method also includes controlling a plurality of switches to direct an electrical signal through the plurality of turns of wire. The plurality of switches electrically coupled to the plurality of turns of wire. The method further includes controlling a switch of the plurality of switches to direct a first portion of a transient current in an opposite direction from a direction of a second portion of the transient current during an off-time.

Abstract: A multi-sensor electromagnetic (EM) system and method for measuring gradients of EM signals. The multi-sensor EM system includes a frame; a transmitter device attached to the frame and configured to generate a primary EM field; a receiver device attached to the frame and configured to record a secondary EM field generated by the earth after being excited by the primary EM field; and a gradient sensor device attached to the frame and configured to record a gradient of the secondary EM field.