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.

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.

Omnidirectional electromagnetic signal inducer (omni-inducer) devices are disclosed. The omni-inducer device may include a housing, which may include a conductive base for coupling signals to ground, and an omnidirectional antenna node including a plurality of antenna coil assemblies, where the node may be disposed on or within the housing. The omni-inducer device may further include one or more transmitter modules for generating ones of a plurality of output signals, which may be generated at ones of a plurality of different frequencies, and one or more control circuits configured to control the transmitters and/or other circuits to selectively switch the ones of the plurality of output signals between ones of the plurality of antenna coil assemblies.

The invention relates to a device having, as a sensor for detecting an object arranged behind an article that is transparent to electromagnetic radiation, a coil assembly having a first transmitting coil (1.1) and a first receiving coil (2.1) arranged orthogonally with respect to the first transmitting. An evaluation unit evaluates the output signals from the coil assembly. The fact that the coil assembly comprises the first transmitting coil (1.1) and at least one further transmitting coil (1.2, 1.3, 1.4), and the first receiving coil (2.1) and at least one further receiving coil (2.2, 2.3, 2.4), wherein axes (1.5, 1.6) of the first and of the at least one further transmitting coil are orthogonal to each other, and the axes (1.5, 1.6) of the first and second transmitting coil intersect the axis (2.5) of the first receiving coil (2.1) that is orthogonal to the first and second transmitting coils (1.1, 1.2), means that a device is provided that reduces or even eliminates the grating effect. According to the method, for this purpose, the electromagnetic fields emitted by the transmitting coils as a result of a periodic AC signal during a first half period are each directed in the direction of the first receiving coil (2.1) and, during the second half period, are directed away from the first receiving call (2.1), wherein the first receiving coil (2.1) is wired and operated in series with at least one further receiving coil (2.2, 2.3, 2.4). An electromagnetic field which penetrates the coil assembly, generates mutually opposed voltages in the receiving coils (2.1, 2.3; 2.2, 2.4).

Various systems and methods for implementing and using a full tensor micro-impedance downhole imaging tool that includes downhole emitters that induce, at azimuthally-spaced positions on a borehole wall, fields having components in three different non-coplanar directions within a formation and directionally sensitive downhole sensors that sense the components caused by each emitter. The tool further includes a downhole controller that processes signals received from the directionally sensitive downhole sensors to provide a set of measurements representative of a 33 impedance tensor at each position.

Various systems and methods are disclosed for implementing and using a multi-axial induction borehole imaging tool that includes emitters that induce, at azimuthally-spaced positions on a borehole wall, a plurality of fields having components in three non-coplanar directions within a formation. The tool also includes directionally sensitive inductive sensors that sense the components caused by each of the one or more inductive emitters, and a downhole controller that processes signals received from the directionally sensitive inductive sensors to provide a set of measurements representative of an impedance tensor at each position.

Conductors of first and second current sensor units are parallel or substantially parallel to each other with a space therebetween. An arch-shaped portion and an inverted arch-shaped portion of the first current sensor unit are at different positions from positions of an arch-shaped portion and an inverted arch-shaped portion of the second current sensor unit. When seen in a width direction, first and second magnetic sensor elements of the first current sensor unit are outside an opening of the second current sensor unit and first and second magnetic sensor elements of the second current sensor unit are outside an opening of the first current sensor unit.

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.

Omnidirectional electromagnetic signal inducer (omni-inducer) devices are disclosed. The omni-inducer device may include a housing, which may include a conductive base for coupling signals to ground, and an omnidirectional antenna node including a plurality of antenna coil assemblies, where the node may be disposed on or within the housing. The omni-inducer device may further include one or more transmitter modules for generating ones of a plurality of output signals, which may be generated at ones of a plurality of different frequencies, and one or more control circuits configured to control the transmitters and/or other circuits to selectively switch the ones of the plurality of output signals between ones of the plurality of antenna coil assemblies.

A measurement vehicle includes a geophysical sensor. One or more operational sensors are configured to detect operational data related to operation of the measurement vehicle. A driving system is configured to move the measurement vehicle in a travel direction relative to a measurement point. A controller is configured to receive information from the geophysical sensor and the operational sensors, and to control the driving system based on the information.