The present disclosure relates to electromagnetic marker devices for locating hidden or buried objects. One embodiment includes an antenna having a plurality of conductive windings enclosed in a housing made of a low dielectric constant material and an electronic circuit including a circuit board having circuit elements disposed thereon and electrically coupled to the conductive windings through a connector. The circuit elements receive an input signal having a first frequency from an above-ground transmitter, convert the input signal to a power supply to power up the electronic circuit, generate, in response to the input signal, an output signal having a second frequency different from the first frequency, and provide the output signal, via the antenna element, to an above-ground receiver.

The present disclosure relates to systems and methods for uniquely identifying buried utilities in a multi-utility region. The system and methods may include sensing magnetic fields upon moving a magnetic field sensing locating device over a multi-utility region comprising a plurality of buried utilities. The sensed magnetic fields may be used to identify a plurality of location data points each indicative of location information pertaining to one or more buried utilities. Based on these location data points, a plurality of clusters may be generated where each cluster may include a set of location data points sharing common characteristics. The generated clusters may exhibit one or more patterns which may be identified and subsequently utilized for classifying the clusters to uniquely identify the buried utilities.

A metal object detection device includes a plurality of detection coils, a capacitor configuring a resonant circuit in cooperation with each of at least two of the detection coils, a first series connection body, a second series connection body, a voltage applying unit, and a processing unit. The voltage applying unit applies an AC voltage to both ends of each of the first series connection body and the second series connection body. The processing unit performs a process for detecting the metal object on the basis of a potential difference between a connection point included in the first series connection body and a connection point included in the second series connection body.

A sensor for the location of metallic objects and also an associated method comprise a plurality of transmitting coils (2.1, 2.2) and at least one receiving coil (1.9) which are arranged such as to be inductively coupled to one another and overlap to a partial extent for the purposes of decoupling the interaction therebetween, whereby there can be obtained a point of optimal cancellation of the interaction. Due to the fact that a flow of current is passed through the transmitting coils (2.1, 2.2) by a sensor electronic system, equal flows of current through the transmitting coils have an effect upon the at least one receiving coil (1.9) which results in a local point of optimal cancellation which moves in a first direction when there is a flow of current in a first transmitting coil (2.1), whereas it moves in another direction when there is a flow of current in a further transmitting coil (2.2), and due to the fact that there is provided a control circuit for the regulation of the currents in the transmitting coils which leads to a displacement of the local point of optimal cancellation which causes cancellation of the received signal, a simple and effective sensor is thereby produced.

A method for obtaining full tensor gain compensated propagation measurements includes processing a full tensor voltage measurement to obtain a fully gain compensated tensor quantity. An electromagnetic logging tool including at least first and second axially spaced transmitters and at least first and second axially spaced receivers is rotated in a subterranean borehole. A plurality of voltage measurements are acquired while rotating to obtain a full tensor voltage measurement which is in turn processed to obtain the fully gain compensated tensor quantity.

The invention detects foreign objects FO near a primary coil 100 of an induction charger. A sensors 111 of a sensor array 110 output sensing signals in response to magnetically coupling the alternating magnetic field 103 produced by the primary coil. A controller 165 connected to each sensor 111 scans the sensing signals and determines whether there is a foreign object perturbing the magnetic field 103 near a sensor. The magnetic field has a spatial distribution that varies by location across the primary coil area. Each sensor has a magnetic field sensing sensitivity that is inversely proportional to the magnetic intensity of the magnetic field produced by the primary coil at a location of the sensor, to reduce the collective dynamic range of the signals, thereby contributing to maintaining a high accuracy in signal sampling. A reference sensor coil 155 compensates for magnetic field drift of the primary coil.

A foreign-object detecting device includes a first coil, a second coil arranged adjacent to the first coil and having the same winding direction as that of the first coil, and foreign-object detecting circuitry. The foreign-object detecting circuitry outputs a first detection signal to an outside or inside terminal of the first coil, outputs a second detection signal having an inverted phase to an outside or inside terminal of the second coil, causes one of the first and second detection signal to flow clockwise, causes the other detection signal to flow counterclockwise to generate a combined magnetic field across a center of the first and a center of the second coil, measures an amount of change in an impedance value of the first or second coils, and determines that a foreign object is present within the combined magnetic field, based on the amount of change.

A foreign matter detection device is mounted on a non-contact power supply system that supplies power in a non-contact manner from a power supply unit to a power reception unit. The foreign matter detection device includes a magnetic field sensor and a magnetic field generation unit. The magnetic field sensor detects an amount of magnetic flux that changes due to foreign matter existing between the power supply unit and the power reception unit. The magnetic field generation unit is provided separately from the power supply unit and the power reception unit, includes a magnetic field generation coil unit, and generates a magnetic field for driving the magnetic field sensor.

Omnidirectional electromagnetic signal inducer (“omni-inducer”) devices are disclosed for generating utility locating current signals, at one or more frequencies in on or more time intervals.

A metal detector with multiple detection zones of alternating polarity achieved by means of multiple coil windings such that when a target moves across it, a detection signal of alternating polarity is generated with a waveform shape which replicates the pattern of zones, a distinctive detection waveform which enables enhanced recognition of target presence while in motion. Balance to external EMI enables the use of large coils for non-swinging searching at high area searching rates.