115results about "Stray field compensation" patented technology

The invention discloses a single-end open type high-performance magnetic shielding system and a design method thereof. The system is formed by combining a passive magnetic shielding subsystem and an active magnetic compensation subsystem. The passive magnetic shielding subsystem is formed by alternately nesting single-end open type high-permeability and high-conductivity metal barrels, and the structure is beneficial to synchronously improving the shielding capability for full-band magnetic interference; the active magnetic compensation subsystem is composed of a group of axial nonlinear gradient coils, two groups of radial nonlinear gradient coils with orthogonal magnetic fields and a magnetic compensation control circuit, and three groups of magnetic compensation coil windings are obtained based on specific nonlinear distributed magnetic interference reverse design in a single-end open type magnetic shielding barrel; different from conventional shimming and linear gradient coils, accurate compensation of magnetic interference in a working area in the barrel can be realized. According to the invention, the shielding capability of the single-end open type magnetic shielding system is improved, and a required near-zero magnetic environment is provided for extremely weak magnetic measurement.

Systems and methods to detect ferromagnetic objects, particularly submerged, non-naturally occurring ferromagnetic objects, account for contributions to the magnetic field arising from topography, such as magnetic refraction at bathymetric slopes. Removing this topography component of noise from detected total magnetic field enhances detection capability of, for example, naval surveillance systems.

A method for extracting information about one or more magnetic sources includes obtaining a first plurality of signals corresponding to magnetic sensor data generated by one or more magnetometers in an unshielded environment at a first time; receiving second information of a direction and a magnitude of a first known magnetic field applied to the one or more magnetometer, the first plurality of signals is acquired while the first known magnetic field is applied and wherein the first known magnetic field encodes directional information of the one or more magnetic sources into the first plurality of signals; extracting the information comprising three-dimensional spatial information of the one or more magnetic sources, respective orientations and strengths of the one or more magnetic sources based on the first information, the second information, and the plurality of signals corresponding to the magnetic sensor data.

The present invention relates to a probe for locating a magnetic marker for use during surgery. The probe comprises at least two first coils (3a, 3b) and at least one second coil (5) arranged substantially coaxially on a longitudinal axis of the probe for measuring the proximity of a magnetic marker to the probe, and a baseline voltage sensing device (7) comprising a first elongated conductor defining a conductive path extending partially around the axis of the probe. The conductive path is constructed and arranged to induce a balanced voltage in the sensing coils that, in use, at least partially offsets the baseline voltage. Methods of manufacturing such a probe, methods of configuring such a probe for use in sensing magnetic markers, and detection devices for locating a magnetic marker during surgery are also disclosed.

A probe for locating a magnetic marker for use in surgery. The probe comprises at least two first coils (3a, 3b) and at least one second coil (5) which are arranged substantially coaxially on a longitudinal axis of the probe for measuring the proximity of a magnetic marker to the probe, and a baseline voltage taring device (7) comprising a first elongate conductor which defines a conducting path extending partially around the probe axis. The conducting path is configured and arranged such that in use the balancing magnetic field induces a balancing voltage in a sense coil that at least partially offsets the baseline voltage. Also disclosed is a method of manufacturing such a probe, a method of setting up such a probe for use in sensing a magnetic marker, and detection apparatus for locating a magnetic marker during surgery.

The present disclosure relates to a method (100) of magnetically calibrating a magnetometer sensing system (30) with respect to an electronic device (50), the method (100) comprising: detecting (110) a disturbing magnetic source (520) in the electronic device (50) relative to a reference coordinate system (X, Y, Z) of the magnetometer sensing system (30); identifying (120) one or more magnetometers (Sk,l) of the magnetometer sensing system (30) which are magnetically affected by the detected disturbing magnetic source (520); selecting (130) one or more balancing magnetic sources (400) to reduce a magnetic effect of the detected disturbing magnetic source (520) on the one or more identified magnetometers (Sk,l); and placing (140) the one or more selected balancing magnetic sources (400) in a fixed relation to the magnetometer sensing system (30) and / or to the disturbing magnetic source (520).

The invention relates to an apparatus and a method for suppressing interference fields in a magnetic sensor. A method (100) for detecting an angular position (theta) of an excitation magnet (15), wherein the method (100) comprises: generating (S100) a magnetic field (B) by the excitation magnet (15); detecting (S110) the magnetic flux density (B1,..., Bn) of the generated magnetic field (B) by means of a number n > = 2 magnetic field sensors (S1,..., Sn) arranged on the main circuit surface (25) of the integrated circuit (20); outputting (S120), to an integrated circuit (20), detection signals (VS1,..., VSn) proportional to the magnetic flux densities (B1,..., Bn) detected by the n magnetic field sensors (S1,..., Sn); performing a first phase correction on the output detection signals (VS1,..., VSn) (S130); converting (S140) the phase-corrected detection signals (VS1 ',..., VSn'); second phase correction is performed on the converted detection signals (Vt1, Vt2) (S150).

In a magnetic field detection device capable of detecting a weak magnetic field without using a shield room, the number of components is reduced, and the circuit structure is simplified. A magnetic field detection device (1) includes: a cancellation coil (C2) wound around a winding core portion (13) of a bobbin (10); magnetic sensors (S1, S21-S24) fixed to mutually different positions of the bobbin (10); and a feedback circuit (31) that cancels an ambient magnetic field of a cancellation space by causing a cancellation current to flow through the cancellation coil (C2) in accordance with an output signal of the magnetic sensor (S1). The magnetic sensors (S21-S24) are disposed within the cancellation space. In this way, a common cancellation coil (C2) is used for the magnetic sensors (S1, S21-S24), so the number of components can be reduced, and the circuit structure can be simplified.

A method related to magnetic field interference and a sensing system are provided. In the method, magnetic field uniformity within a time period is determined. Movement situation within the time period is determined. Magnetic field interference situation is determined according to the magnetic field uniformity and the movement situation.

A soft magnetic sensor comprising a soft material containing randomly distributed magnetic microparticles and a magnetometer that can estimate force and localize contact over a continuous area. A reference magnetometer can be used to filter motion and ambient noise. Methods for locating contact and determining force comprise data analysis of the magnetometer output. In some embodiments, the sensor can localize an object prior to contact.

Provided is a magnetic sensor capable of detecting a magnetic field by closed-loop control even if the magnetic field to be measured is weak. This magnetic sensor is provided with: magnetic layers (41, 42) facing each other via a magnetic gap (G1); a magnetosensitive element (R1) disposed on a magnetic path formed by the magnetic gap (G1); and a compensation coil (60) that generates a cancellation magnetic flux ([phi] 4) that cancels the magnetic flux ([phi] 2) applied to the magnetosensitive element (R1). According to the present invention, since the magnetic flux ([phi] 2) flowing through the magnetic layers (41, 42) functioning as a yoke is applied to the magnetosensitive element (R1), detection can be performed even if the magnetic field to be measured is weak. In addition, since a compensation coil (60) that cancels out the magnetic flux ([phi] 2) is provided, closed-loop control can also be performed.

Various embodiments disclosed herein comprise a system. The system comprises a coil, a magnetic field sensor, and a controller. The coil generates a spatially and temporally varying magnetic field. The magnetic field sensor measures the magnetic field and a background magnetic field. The magnetic field sensor provides a magnetic field measurement and a background magnetic field measurement to the controller. The controller determines the position and orientation of the magnetic field sensor based on the magnetic field measurement and the background magnetic field measurement. The controller transfers control signaling to modify the magnetic field based on the position and orientation of the magnetic field sensor to null the background magnetic field. The coil receives the control signaling and modifies the spatially and temporally varying magnetic field based on the control signaling to null the background magnetic field.

A generation method for a magnetic configuration of a magnetic material includes: obtaining an initial magnetic configuration and an initial atomic configuration of the magnetic material; and randomly generating a variety of random configuration combinations; selecting one of the random configuration combinations as a target magnetic configuration and a target atomic configuration, to obtain a constraint constant and a wave function of the target magnetic configuration; determining energy, temperature and pressure, and storing them; returning to select a new random configuration combination, and repeating the above steps by using different magnetic materials; obtaining the magnetic material of a specified phase transition temperature. The present disclosure also provides and a simulation method for a magnetic configuration of a magnetic material, which can simulate the target magnetic configuration to form a magnetic configuration library and guide the synthesis of the target magnetic materials.

The present invention relates to a method for determining the coupling between magnetometers in an array of N magnetometers (e.g., by means of an optically pumped magnetometer), wherein each magnetometer includes a field cancellation system that can be enabled to operate the magnetometer in a zero field. The method includes a first phase (P1), in which the N magnetometers are divided into N - 1 magnetometers with the field cancellation system deactivated and one measuring magnetometer with the field cancellation system activated. The first phase includes: - generating (GENj) by these magnetometers a plurality of reference magnetic fields with known amplitudes and different directions, - measuring (MESi) by the measuring magnetometer the ambient magnetic field on a plurality of measurement axes, - determining (CALCij) the coupling coefficient between the measuring magnetometer and each of the N magnetometers based on the measured values and these known amplitudes.

A probe for locating magnetic markers used in surgery. The probe includes: at least two first coils (3a, 3b) and at least one second coil (5), which are arranged substantially coaxially on the longitudinal axis of the probe for measuring the proximity of the magnetic marker to the probe; and a reference voltage balancing device (7) comprising a first elongated conductor defining a conductive path extending partially around the probe axis. The conductive path is configured and arranged such that, in use, a balancing magnetic field induces a balancing voltage in the sensing coil that at least partially cancels out the reference voltage. Methods for manufacturing such a probe, methods for setting such a probe for sensing magnetic markers, and detection devices for locating magnetic markers during surgery are also disclosed.

A three-axis magnetic field detection device includes a magnetic field conversion unit for generating a stray field having a magnetic field direction according to a magnetic field direction of an outer magnetic field using magnetic particles, a magnetic field measurement unit for measuring a magnetic field direction with respect to an X-axis magnetic field and Y-axis magnetic field in relation to the outer magnetic field, and a magnetic field detection unit for detecting the X-axis magnetic field, the Y-axis magnetic field and the Z-axis magnetic field based on the stray field and the measured magnetic field direction.

A probe (303; 403) for sensing a magnetic marker, comprising a first coil set (313; 413) including a first coil of a first coil type, e.g., a sense coil (305; 405), disposed between a first pair of coils of a second coil type, e.g., a drive coil (301a, 301b; 401a, 401b) connected in series, and a balance element (317; 417) axially spaced from the first coil set (313; 413) along the length of the probe (303; 403). The balance element (317; 417) is configured or arranged to generate a sense voltage that fully offsets, partially offsets, or minimizes a sense voltage induced in one or more sense coils (305; 405) of the first coil set from the drive coil or coils (301a, 301b; 401a, 401b). A detection system is also disclosed, comprising the probe (303; 403), a magnetic field generator configured to drive an alternating magnetic field through the drive coils (301a, 301b; 401a, 401b) of the first coil set and the balance element (317; 417), and at least one detector configured to receive a signal indicative of a sensed voltage.

The invention relates to a magnetoresistive sensor (500). A magnetoresistive sensor (500) includes a layer stack (510) having at least one reference layer (512) having a reference magnetization perpendicular to a plane of the layer stack and at least one free layer (516) having a vortex magnetization. The magnetoresistive sensor (500) further comprises at least one soft magnetic shield (520) arranged adjacent to the layer stack, which soft magnetic shield is designed to reduce the influence of an external magnetic field on the free layer (516) along the shield axis (530).

A magnetoresistive sensor includes a layer stack containing at least one reference layer having a reference magnetization perpendicular to the plane of the layer stack and at least one free layer having a vortex magnetization. The magnetoresistive sensor furthermore includes at least one soft-magnetic shield arranged adjacent to the layer stack and configured to reduce an influence of an external magnetic field along a shielding axis on the free layer.

The application discloses an aviation magnetic interference suppression method, device and equipment based on double-machine multi-magnetic sensors, wherein two magnetic sensors are arranged on two magnetic exploration airplanes respectively, the two magnetic exploration airplanes are located at the same height, and the height difference between any one of the magnetic exploration airplanes and a position of a detection target is h; the two magnetic exploration airplanes are apart from each other by L; the detection distances of the two magnetic exploration airplanes are both R; it can be guaranteed that the two magnetic exploration airplanes cannot measure the target signal at the same time, so that only one of the common-mode magnetic signals of the magnetic exploration airplanes contains the target signal and the diurnal magnetic interference signal, and the common-mode signal of the other magnetic exploration airplane contains only the diurnal magnetic interference signal; the target signal after the diurnal magnetic interference signal is removed can be obtained by subtracting the common-mode signals of the two magnetic exploration airplanes; and the diurnal magnetic interference signal can be better suppressed through the method, so that the accuracy of the target signal is improved.

A method and system for use in reducing magnetic fields generated by an electrical system includes determining one or more current-carrying loops in electrical wiring of an electrical system, providing a parallel wire loop to at least one of the one or more current-carrying loops generally overlapping a physical path of the at least one current-carrying loop, connecting the parallel wire loops to a power system having at least one sensor, operating the at least one current sensor to provide sensed data indicative of a current passing through the at least one current-carrying loop, and operating the power system based on the sensed data to transmit a current through the parallel wire loop in a direction opposite to the current passing through the at least one current-carrying loop, thereby eliminating a magnetic field generated by the current passing through the current-carrying loop.

Methods, apparatuses, and systems for detecting a stray magnetic field are provided. An example apparatus may include a first magnetic sensor element at a first position relative to a magnetic field source to detect a target magnetic field emitted by the magnetic field source, a second magnetic sensor element at a second position relative to the magnetic field source to detect the target magnetic field emitted by the magnetic field source, and a processor element electronically coupled to the first magnetic sensor element and the second magnetic sensor element. In some examples, the processor element may be configured to: receive a first output from the first magnetic sensor element, receive a second output from the second magnetic sensor element, and detect the stray magnetic field interfering with the target magnetic field based at least in part on the first output and the second output.

The present invention discloses a dual Helmholtz control device for dynamic magnetic field compensation, comprising: a reverse Helmholtz coil, a forward Helmholtz coil, a fluxgate sensor, a uniform field compensation module, and a gradient compensation module; the reverse Helmholtz coil and the forward Helmholtz coil are parallel and opposite to each other, and are used to generate an induced magnetic field; the fluxgate sensor is used to convert the magnetic induction intensity of the induced magnetic field into a voltage signal; the uniform field compensation module is used to provide a gradient magnetic field for the reverse Helmholtz coil to cancel the non-uniform term in the geomagnetic field; the gradient compensation module is used to make the forward Helmholtz coil generate a corresponding bias uniform magnetic field to cancel the uniform term in the geomagnetic field. The dual Helmholtz coil structure adopted by the present invention compensates the uniform term and the non-uniform term in the geomagnetic field while reducing the size of the shielding device, and can provide an extremely weak magnetic environment with a large uniform area.

A method of diagnosing internal characteristics of a device includes applying a strong magnetic field to the device. The method can include reducing the strong magnetic field at a location of one or more sensors. At least one of the one or more sensors is proximate to the device. The method can include measuring induced magnetic fields around the device. The method can include measuring induced or intrinsic electrical current flow. The method can include measuring intrinsic magnetic properties. The induced magnetic fields can include diagnostic information on properties of the device and how the properties change over time. The device may be, for example, a battery, a capacitor, a supercapacitor, or a fuel cell. The presented measurement of magnetic susceptibility can be performed on materials, solutions, chemical substances, or tissue samples.

Disclosed is a method to remove distortion from a navigation system. The navigation system may be used to perform a procedure on a subject. The procedure may be any appropriate procedure. The navigation system may be used to account for the distortive effects of various conductive objects positioned near the subject on which the procedure is performed.

Influence of RF noise and external magnetic field on the image quality of a portable magnetic resonance imaging (MRI) system (1) are to be avoided. This is achieved by providing a system and a computer-implemented method for determining an optimized position and / or orientation of a portable MRI system (1) for an MR imaging process in a medical environment (2), comprising at least one RF noise sensor (3), wherein the RF noise sensor (3) is configured for measuring RF noise in the medical environment (2) and to provide sensor data, at least one magnetic field sensor (4), wherein the magnetic field sensor (4) is configured to measure the external magnetic field in the medical environment (2) and to provide sensor data, a processor unit (5), wherein the sensors (3, 4) are connected to the processor unit (5), the processor unit (5) comprising at least one memory (6) for storing instructions, at least one processor (7) configured to execute the instructions to cause the following to be performed: measuring RF noise and the external magnetic field in the medical environment by means of corresponding sensors (3, 4), evaluating the sensor data and creating spatial distributions of the measured RF noise and / or the measured external magnetic field in the medical environment (2), determining a position and / or orientation of the portable MRI system (1) in the medical environment (2) for an MR imaging process based on the spatial distributions of the measured RF noise and / or the measured external magnetic field.

An unmanned aerial vehicle (UAV) 100 carries an optically pumped magnetometer 110 for detecting a signal from a magnetic beacon. The UAV has one or more rotors 106 which produce a noise signal. The ma