A foreign object detector for detecting a foreign object between a transmission pad and a reception pad of a wireless charging system can include a plurality of object detectors; and a detection circuit configured to detect an object based on data received from the plurality of object detectors, in which each of the plurality of object detectors includes a first coil part including a coil wound in a first rotation direction; and a second coil part stacked on the first coil part and including a coil wound in a second rotation direction different from the first rotational direction, and in which each of the plurality of object detectors is connected in series or in parallel with one another.

An example method for determining borehole acoustics using an electromagnetic sensing apparatus may include positioning a downhole tool within a borehole disposed in a formation. The downhole tool may comprise at least one acoustic source and at least one electromagnetic (EM) sensor. An acoustic wave may be emitted from the at least one acoustic source. The acoustic wave may generate an electrical signal when an EM field is present within the borehole. The electrical signal may be measured with the at least one EM sensor. At least one downhole characteristic may be determined based, at least in part, on the measured electrical signal.

A movement detection unit includes a movable body, a first sensor, a second sensor, and a signal processor. The movable body performs a movement in a first direction. The first sensor detects a first magnetic field change which is caused by the movement of the movable body and outputs a first signal. The second sensor is provided in the first direction at a location different from a location of the first sensor. The second sensor detects a second magnetic fled change which is caused by the movement of the movable body and outputting a second signal. The signal processor includes a signal generating circuit that generates a third signal and a fourth signal on a basis of the first signal. The third signal and the fourth signal have waveforms different from each other.

A method of detecting contraband about a person using a portable detector apparatus having an elongate housing that supports at least one magnetic sensor, which is arranged to produce a signal indicative of an ambient magnetic field or gradient over a zone of sensitivity which extends away from the housing, the size of the zone large enough to contain the whole body of the person, and a signal processing circuit that receives as an input the signal from the magnetic sensor and which, in response to a change in the signal, produces an alert signal includes setting up the portable detector apparatus in a chosen location, causing the person to pass alongside the housing from outside of the zone of sensitivity into the zone of sensitivity, and monitoring for the issue of an alert by the device which is indicative of the possible presence of contraband.

Disclosed are methods and apparatus for identifying non-metallic subterranean structures using amorphous metal markers associated with the structures. Some examples will include the amorphous metal in the form of one or more sections of an amorphous metal foil within a protective enclosure sufficient to physically isolate the amorphous metal foil from the surrounding Earth. The amorphous metal foil and enclosure may be in the form of a tape which either will be secured to, or placed proximate the subterranean structure, which may be, for example, a pipe or conduit, or other non-metallic structure.

A security screening apparatus for use in detecting ferromagnetic objects comprises a detector apparatus which comprises a housing that supports at least one magnetic sensor arranged to produce a signal indicative of an ambient magnetic field or gradient over a zone of sensitivity which extends away from the housing, the size of the zone being large enough to contain the whole body of the person, and a signal processing circuit which receives as an input the signal from the magnetic sensor and which, in response to a change in the signal produces an alert signal. A beacon that comprises a light source is able to emit at least two visually distinct colors of light, and a control means controls the light source such that in a first condition in the absence of the alert signal the beacon emits a first color light and in a second condition corresponding to the presence of the alert signal the beacon emits a second, different, color of light. The light source is arranged such that the position and/or size and/or shape of the illuminated area of the light source in the first condition is different from the position and/or size and or shape of the illuminated area of the light source in the second condition.

A system and method for airborne geophysical exploration over the ground are disclosed. In one embodiment of the system, two towing bodies are towed behind an aircraft in flight in a vertically spaced-apart relation above a ground station. Respective magnetometer measurement instruments are located within each of the towing bodies and the ground station. Each magnetometer measurement instrument collects total field magnitude data to contribute to the magnetic vertical gradient data relative to magnetic crustal anomalies of geological origin and variations in an ambient magnetic field above the surface area of the survey. Each magnetometer measurement instrument also collects location, time, and inertial data substantially simultaneously with the total field magnitude data to provide position-correlated measurements thereof.

A security screening apparatus for use in detecting ferromagnetic objects comprises

a detector apparatus which comprises a housing that supports at least one magnetic sensor arranged to produce a signal indicative of an ambient magnetic field or gradient over a zone of sensitivity which extends away from the housing, the size of the zone being large enough to contain the whole body of the person, and a signal processing circuit which receives as an input the signal from the magnetic sensor and which, in response to a change in the signal produces an alert signal. A beacon that comprises a light source is able to emit at least two visually distinct colours of light, and a control means controls the light source such that in a first condition in the absence of the alert signal the beacon emits a first colour light and in a second condition corresponding to the presence of the alert signal the beacon emits a second, different, colour of light. The light source is arranged such that the position and/or size and/or shape of the illuminated area of the light source in the first condition is different from the position and/or size and or shape of the illuminated area of the light source in the second condition.

A system and method for airborne geophysical exploration over the ground are disclosed. In one embodiment of the system, two towing bodies are towed behind an aircraft in flight in a vertically spaced-apart relation above a ground station. Respective magnetometer measurement instruments are located within each of the towing bodies and the ground station. Each magnetometer measurement instrument collects total field magnitude data to contribute to the magnetic vertical gradient data relative to magnetic crustal anomalies of geological origin and variations in an ambient magnetic field above the surface area of the survey. Each magnetometer measurement instrument also collects location, time, and inertial data substantially simultaneously with the total field magnitude data to provide position-correlated measurements thereof.

A cost-effective aerial detector device is configured to locate ferromagnetic objects in a survey area. The aerial detector device includes a UAV, a sensor housing suspended from the UAV, and the sensor module inside the sensor housing. The sensor module can be a smartphone that includes a magnetometer and a GPS unit. A method for locating a ferromagnetic target within the survey area includes the steps of launching the aerial detector device into the survey area, activating the magnetometer and GPS unit on the smartphone to obtain magnetic field measurements and location information, correlating the magnetic field measurements with corresponding location information to produced geolocated magnetic field data, identifying geolocated magnetic anomaly data from the geolocated magnetic field data, identifying one or more magnetic anomaly signatures for the ferromagnetic target, and determining the location of the ferromagnetic target from the location information associated with the target magnetic anomaly signature.