82results about "Magnetic gradient measurements" patented technology

The invention discloses a detection method of an ocean magnetic field sensor based on a diamond NV color center. The detection method comprises the following steps: S1, calibrating a base line; s2, alternately measuring fluorescence between two single quantum resonance frequencies, and obtaining a difference to realize DQ reading; s3, three-axis compensation current is adjusted based on closed-loop control, and the NV working point is maintained at zero magnetization bias; s4, obtaining background magnetic field change through digital demodulation and adaptive filtering; and S5, calculating a gradient based on the spatial difference of the multi-point light spots, judging the existence and trajectory of the underwater vehicle in combination with a threshold value and a spectrum matching method, calibrating the threshold value according to the magnetic field characteristics of the existing underwater vehicle, adopting short-time Fourier transform signal spectrum, comparing the threshold value with known submarine characteristic spectrum data, and prompting if the similarity exceeds a set threshold value. According to the detection method, the measurement precision and the anti-interference capability can be improved, and the method is suitable for real-time monitoring of weak magnetic anomalies (such as magnetic moment disturbance of an underwater vehicle).

The invention discloses an underwater magnetic field measuring device based on a diamond NV color center. The underwater magnetic field measuring device comprises a diamond NV color center module, an incident laser excitation module, a multi-path optical coupling module, a microwave excitation module, a fluorescence acquisition and photoelectric conversion module, a signal processing and control module and a magnetic field module, the multi-path optical coupling module is used for dividing an optical fiber into multiple paths and collecting fluorescence generated by the diamond block; the microwave excitation module is used for switching between two single-quantum resonance frequencies to drive an NV color center to realize double-quantum DQ reading; and the signal processing and control module comprises an FPGA (Field Programmable Gate Array) processing unit of a field programmable logic array chip. According to the invention, a dual-quantum DQ working point of a diamond NV color center is used as a measurement channel, common-mode influence of D is removed through differential measurement, the problem of D drift caused by temperature drift, stress and material aging is physically and obviously inhibited, and the device can still realize ultrahigh-sensitivity measurement in a complex underwater environment.

The invention concerns a handheld mobile device for determining a safety hazard due to magnetic fields, in particular a mobile phone, comprising a sensor unit comprising at least one magnetic field sensor and a position sensor; wherein the magnetic field sensor is configured to measure a magnetic field vector of an environment of the handheld mobile device; wherein the position sensor is configured to measure a position information of the handheld mobile device; a processing unit configured to calculate magnetic field data based on the measured magnetic field vector and the position information, wherein the magnetic field data comprises at least one of a strength of a magnetic field, magnet field gradient, a magnetic force, and electromagnetic induction, and determine whether the handheld mobile device is in a range of a magnetic fringe field of a Magnetic Resonance system based on the calculated magnetic field data. The invention further concerns a method for determining a safety hazard due to magnetic fields for a handheld mobile device, in particula2r a mobile phone.

The utility model relates to an unmanned aerial vehicle for underground electromagnetic anomaly detection, and belongs to the technical field of unmanned aerial vehicle detection. Comprising an unmanned aerial vehicle body; the magnetic gradient detection device is carried on the unmanned aerial vehicle body; the magnetic gradient detection device comprises a telescopic supporting arm, a posture switching mechanism and at least two magnetic sensing units. The at least two magnetic sensing units are arranged at intervals in the axial direction of the telescopic supporting arm; the posture switching mechanism is connected with the unmanned aerial vehicle body and the telescopic supporting arm and used for driving the telescopic supporting arm to be switched between the horizontal storage position and the vertical working position. The vertical distance between the at least two magnetic sensing units is obviously increased in the vertical direction, and the requirement of geomagnetic vertical gradient measurement for the length of a sensor base line is met.

Disclosed are methods and devices for detecting retained surgical items or other objects having a magnetic signature within a corpus of a patient. The device can comprise a handle, a shaft extending from the handle, and a distal sensing portion positioned distally of the shaft. The distal sensing portion can comprise one or more gradiometers comprising a plurality of magnetometers. The device can further comprise one or more output components configured to generate a user output to alert a user of a detected object.

An apparatus for generating magnetic field gradients, comprising (a) a first planar electromagnetic coil set configured to generate a first magnetic field gradient with respect to a first axis, (b) a second planar electromagnetic coil set configured to generate a second magnetic field gradient with respect to a second axis orthogonal to the first axis, (c) a third planar electromagnetic coil set configured to generate a third magnetic field gradient with respect to a third axis orthogonal to the first and second axes, and (d) a controller configured to selectively power the first, second, and / or third electromagnetic coil sets to sequentially generate positioning magnetic field gradients with respect to each of the first, second, and third axes, at least a portion of each positioning magnetic field gradient having a magnetic field magnitude that monotonically varies along the respective axis.

The application relates to the technical field of magnetic detection, in particular to a method and a test system for coupling a magnetic gradiometer and a SQUID to improve sensitivity, which comprises the following steps: deploying at least one set of magnetic gradiometer probe arrays in a superconducting shielding environment to obtain original magnetic gradiometer tensor data streams of a target area; feeding a multi-channel SQUID front-end input coil through a superconducting transmission line; completing magnetic flux locking and amplification to generate a preliminary signal by the SQUID; suppressing environmental and SQUID background noise by using an adaptive digital noise reduction processor to obtain a high-fidelity magnetic gradiometer signal; and generating a high-resolution magnetic gradiometer distribution map through gradient reconstruction and spatial resolution enhancement. The superconducting shielding environment combines array acquisition to suppress external interference and retain complete tensor characteristics, and the superconducting transmission line combines a multi-channel SQUID to reduce transmission noise and cumulative error, so that the signal is closer to the original state, and the SQUID locking sensitivity and amplification fidelity are improved. The application improves the sensitivity of magnetic gradiometer detection and the accuracy of target identification.

The invention discloses a magnetic target attitude measurement method based on gradient tensor. According to the method, gradient tensor measurement information on a measurement surface is utilized, the plane distribution of the equivalent attenuation magnetic moment is obtained through conversion calculation, the local maximum point projection can be regarded as the horizontal position of the target, and the influence of a slowly-varying background magnetic field is eliminated by utilizing the difference characteristic of the gradient tensor; the influence of attitude jitter of the measurement platform is overcome by using the rotation invariance of the equivalent attenuation magnetic moment information, and the projection of the maximum value point of the measurement surface has no systematic deviation; building a quasi-linear equation between the measured value and the target vertical depth and the equivalent magnetic moment by using the equivalent attenuation magnetic moment of the effective measurement point, and further accurately and quickly obtaining the target vertical depth and the equivalent magnetic moment; meanwhile, the possible solution of the equivalent magnetic moment direction of the target is estimated by using the gradient tensor characteristic values and the characteristic vectors of the plurality of effective measurement points, and the real magnetic moment direction of the target is screened out through statistical analysis, so that the target attitude measurement is realized, and the result is steady.

Method (500) of determining a gradient (G1) of a magnetic field generated by a magnetic source, comprising the steps of: a) providing a first sensor signal (s1) by a first magnetic sensor located at a first sensor location (p1); b) providing a second sensor signal (s2) by a second magnetic sensor located at a second sensor location (p2) located at a second sensor location (p2); c) determining a difference (DIFF12) between the first and the second sensor signal (s1,s2); d) determining said gradient (G1) as a value proportional to a combination of said difference (DIFF12) and a correction term (CORR12) being a predefined function of the first and the second signal (s1, s2), e.g. as G1=(s1-s2)+w*(s1+s2). A device or system configured for performing this method.

The invention concerns a handheld mobile device for determining a safety hazard due to magnetic fields, in particular a mobile phone, comprising a sensor unit comprising at least one magnetic field sensor and a position sensor; wherein the magnetic field sensor is configured to measure a magnetic field vector of an environment of the handheld mobile device; wherein the position sensor is configured to measure a position information of the handheld mobile device; a processing unit configured to calculate magnetic field data based on the measured magnetic field vector and the position information, wherein the magnetic field data comprises at least one of a strength of a magnetic field, magnet field gradient, a magnetic force, and electromagnetic induction, and determine whether the handheld mobile device is in a range of a magnetic fringe field of a Magnetic Resonance system based on the calculated magnetic field data. The invention further concerns a method for determining a safety hazard due to magnetic fields for a handheld mobile device, in particular a mobile phone.

The present application provides a kind of gradient magnetic field sensor, wherein: with: alternating current power connection terminal, it is connected with the 1st power terminal that alternating current power has;1st magnetic core, it is connected between the alternating current power connection terminal and ground wire;2nd magnetic core, it is connected in parallel with the 1st magnetic core between the alternating current power connection terminal and ground wire;Alternating current control unit, it is connected between the alternating current power connection terminal and at least one of the 1st magnetic core and the 2nd magnetic core, controls the alternating current that flows through at least one of the 1st magnetic core and the 2nd magnetic core;1st detection coil, it is wound in the 1st magnetic core;2nd detection coil, it is wound in the 2nd magnetic core, and is differentially connected with the 1st detection coil;And detection circuit, it detects the voltage corresponding to the difference between the 1st voltage output from the 1st detection coil and the 2nd voltage output from the 2nd detection coil.

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.

A system, comprising: a reference magnetic field source that is configured to generate a reference magnetic field; a plurality of magnetic field sensing elements arranged in a sensing bridge, the sensing bridge being configured to sense the reference magnetic field and an external magnetic field simultaneously, the sensing bridge being configured to output a first signal and a second signal; a first circuit that is configured to generate a common mode signal of the sensing bridge based on the first signal and the second signal; an adjustment circuit that is configured to adjust a sensitivity of the sensing bridge based, at least in part, on a common mode signal of the sensing bridge; and a processing circuitry that is configured to use a differential signal of the sensing bridge to generate an output signal, the differential signal being based on a strength of the external magnetic field.

This invention provides a biaxial magnetic field measurement gradient meter based on the spin-free exchange relaxation effect, comprising: a gas cell unit including a heating element and a magnetic shielding element, wherein the heating element contains an alkali metal gas cell; a pump light unit including a first optical platform and a pump light path disposed on the first optical platform, wherein the pump light generated by the pump light path is used to polarize the alkali metal atoms in the alkali metal gas cell; and a detection light unit including a second optical platform and a detection light path disposed on the second optical platform, wherein the detection light generated by the detection light path passes through the alkali metal gas cell twice to obtain the magnetic field gradients along the X and Y axes. Because the detection light generated by the detection light path can enter the alkali metal gas cell twice, simultaneous measurement of the biaxial magnetic field gradients along the X and Y axes is achieved, thereby reducing the influence on the relaxation of alkali metal atoms and reducing the influence on the signal differential effect in magnetic field measurement, thus reducing the limitations on improving magnetic field sensitivity in magnetic field measurement.

To provide an integrated magnetometer and a method for detecting a magnetic field.SOLUTION: The present invention relates to an integrated magnetometer and a method for detecting a magnetic field. In particular, the present disclosure relates to a sensor for detecting ferromagnetic or superparamagnetic structures on a material surface. The integrated magnetometer (600) comprises at least one magnetic field sensor unit (604, 606) comprising a first transducer element (RH1, RH2; RH3, RH4) for generating a first electrical output signal in response to a detected magnetic field, and a second transducer element (RH5, RH6; RH7, RH8) for detecting a magnetic field at two different locations, and at least one gradient sensor unit (608, 610) comprising at least a pair of second transducer elements (RG1, RG2; RG3, RG4) arranged to generate a second electrical output signal in response to a detected magnetic field, wherein the first transducer elements and the second transducer elements are formed on a common substrate (616) and surrounded by a common protection layer and / or housing (618).SELECTED DRAWING: Figure 6

Provided is a gradiometer coil system (100; 302; 304; 306) for measuring a magnetic field emanating from a specimen located within the coil system (100; 302; 304; 306). The system comprises at least one receiving coil section (102; 202; 302a), which is sensitive to the mag netic field. Additionally, the system includes at least one compensation coil section (104a, ..., 104d; 204a, ..., 204d; 302b) connected in series with the receiving coil section (102; 202; 302a). The compensation coil section (104a, ..., 104d; 204a, ..., 204d; 302b) is arranged to compensate for external magnetic fields affecting the receiving coil section (102; 202; 302a). Furthermore, the area enclosed by the compensation coil section (104a, ..., 104d; 204a, ..., 204d; 302b) is smaller than the area enclosed by the receiving coil section (102; 202; 302a).

The application discloses a kind of single-point magnetic gradient positioning method and device for motion platform, install "H" shape magnetic sensor array in motion platform, utilize magnetic field gradient information in magnetic field X direction, calculate the position information and magnetic moment information of target;Using the position and magnetic moment information calculated, the magnetic anomaly Y direction gradient information that the point produces in the measurement point of the magnetic target is calculated by magnetic dipole target forward process;Using the measured Y direction gradient of the measurement point and model forward theory Y direction gradient, calculate the symmetric average absolute percentage error;Finally, whether the symmetric average absolute percentage error of the measurement point is minimum value is judged, to judge whether it is CPA point.The application is realized by the magnetic field gradient information at CPA point, the acquisition of target position and magnetic moment information, solve the problem that larger positioning error is caused by inconsistent measurement state in the magnetic positioning method based on multiple measurement points, improve the positioning performance of target.

This invention relates to the field of geomagnetic vector measurement technology and proposes an in-situ rapid calibration method for a cubic magnetic gradient tensor measurement array. This invention utilizes a triaxial Helmholtz coil system to generate a constant magnetic field with random orientation and actively compensates for environmental magnetic drift. A hierarchical calibration algorithm is used to sequentially estimate sensor-level inherent errors and array-level alignment errors, and an evaluation framework based on tensor invariants is established to quantitatively analyze the calibration effect. Specifically, this includes: constructing a constant modulus random magnetic field, solving the hierarchical calibration algorithm, and evaluation and verification based on tensor invariants. This invention eliminates the need for mechanical array rotation, achieving in-situ rapid calibration in a static array state. It significantly suppresses pseudo-gradients introduced by channel inconsistencies, improving the stability of magnetic gradient tensor measurement by 3 to 5 orders of magnitude. It is applicable to magnetic anomaly detection and target localization scenarios in fields such as geological exploration, underwater tracking, and space magnetic surveying.

A security switch for detecting an actuator comprises a magnetic field source, a magnetically susceptible object, and a circuit. The magnetic field source is configured to produce a magnetic field gradient. The magnetically susceptible object is suspended at a first position at least in part due to the magnetic field gradient and shiftable to a second position when the actuator affects the magnetic field gradient. The circuit is configured to detect when the object is in the second position.

The application discloses a kind of optimization methods of residual magnetism measurement process in magnetic resonance imaging system, adopt positive and negative combination gradient as test gradient, the difference of the action of spin echo and gradient echo is combined with magnetic field inhomogeneity, the change of magnetic field uniformity caused by test gradient is measured, then the change of echo peak caused by the change is used to measure the strength of residual magnetism.The method avoids the reference test under the condition that test gradient is zero, overcomes the adverse effects of magnetic hysteresis on reference signal, ensures that the magnetic field distribution state when collecting echo signal in measurement process is determined and stable, eliminates the influence of test sequence on test result, so as to improve the accuracy and stability of residual magnetism measurement result.The method of the application is simple and easy to operate, can measure the spatial anisotropy of residual magnetism, can be used to evaluate the influence of residual magnetism on imaging space positioning, and is especially suitable for judging whether permanent magnetic resonance imaging system meets the requirements of space positioning for monitoring and navigation in interventional therapy.

In one embodiment, a method includes, by an electronic device, accessing a first series of first magnetic values that represents a first magnetic recording that comprises a first set of first magnetic measurements that are each represented by one of the first magnetic values. The method includes, by the electronic device, accessing a second series of second magnetic values that represents a second magnetic recording that comprises a second set of second magnetic measurements that are each represented by one of the second magnetic values. The method includes, by the electronic device, approximately aligning the first and second series with each other; calculating a difference between the first and second series as aligned with each other; determining a similarity between the first and second series based on the difference; and performing navigation or localization based on the determined similarity.

A current sensor system for accurately measuring AC currents with frequencies up to 2 kHz includes: an electrical conductor (e.g., a busbar) for conducting the AC current to create a first magnetic field; a magnetic sensor device for measuring a component or gradient of the magnetic field; and an object (e.g., a metal plate) having a conductive surface disposed near the conductor to allow eddy currents to flow in the surface, thereby creating a second magnetic field superimposed on the first magnetic field; wherein the magnetic sensor device is configured to determine the current as a signal or value proportional to the measured component or gradient. The metal plate may have openings. The current sensor system may further include a shield.

Size, weight, and cost of an atomic magnetic sensor vacuum chamber, and thus an atomic magnetometer and / or an atomic magnetic gradiometer, is reduced by using at least one photonic integrated circuit (PIC). The at least one PIC is configured to receive an optical signal, e.g., from a laser, and to distribute the optical signal to at least one set of two or more grating coupled surface emitters. Each grating coupled surface emitter is configured to collimate, direct, and emit, along a direction of emission, an optical beam, derived from a portion of the optical signal, to an optical detector.

In one embodiment, a method includes accessing a first series of first magnetic values that represents a first magnetic recording that includes a first set of first magnetic measurements. Each of the first magnetic values represents one of the first magnetic measurements. The method includes accessing a second series of second magnetic values that represents a second magnetic recording that includes a second set of second magnetic measurements. Each of the second magnetic values represents one of the second magnetic measurements. The method includes approximately aligning the first and second series with each other; calculating a difference between the first and second series as aligned with each other; and determining a similarity between the first and second series based on the difference.

This disclosure describes a sensing capability resistant to crosstalk. A current sensor is provided for a target conductor among a plurality of conductors. The current sensor includes at least one magnetic sensor configured to provide two signals representing two different parameters of a field, the two different parameters being different components or their directional derivatives (e.g., gradients). The current sensor also includes a processor configured to derive a signal indicating a current based on a linear combination of a first signal and at least a second signal. At least one of these signals is weighted by coefficients that are constants selected based on the distance between the sensor and at least one of the plurality of conductors in at least a first or second direction. The coefficients are selected to reduce the contribution of parasitic magnetic fields to the signal indicating a current in the first conductor, wherein the parasitic magnetic field is generated by at least one other conductor.

A method of determining an orientation of a magnet which is pivotable about a reference position having a predefined position relative to a silicon substrate, includes: providing a silicon substrate; determining a first / second magnetic field gradient along a first / second direction; determining a first / second angle based on said first / second magnetic field gradient and a first / second correction value. A sensor device configured for performing this method. A sensor system includes such sensor device and a magnet, optionally connected to a joystick.

The invention provides a steel nondestructive testing method and system based on multi-modal data, and relates to the technical field of material detection. The method comprises the following steps: identifying a starting moment when steel enters a plastic deformation stage based on an acoustic emission signal sequence of the steel in a stress process, and determining a time interval when the active degree of an acoustic emission signal rises; acquiring a metal magnetic memory signal and surface strain data in the time interval; further, the magnetic field gradient abnormal position and the strain concentration area position of the steel are determined; determining a multi-modal signal space overlapping region; and performing multi-scale decomposition on the acoustic emission signals in the multi-modal signal space overlapping region, determining the accumulation degree of irreversible change of the microstructure of the steel based on abrupt change characteristics in the decomposed signals, and then determining the detection result of the steel. According to the application, dynamic monitoring of transition from an elastic stage to a plastic deformation stage in a stress process of the steel can be realized, and internal microstructure change of the steel is accurately identified and spatial positioning is performed.

A method (1900) of determining an orientation (α, β) of a magnet which is pivotable about a reference position having a predefined position relative to a silicon substrate, comprising: providing a silicon substrate; determining a first / second magnetic field gradient along a first / second direction; determining a first / second angle (α, β) based on said first / second magnetic field gradient and a first / second correction value (D1 to D8). The first / second correction value is related to (e.g. indicative of) the magnetic field strength of the magnet and / or is substantially independent of the orientation of the magnet. A sensor device configured for performing this method. A sensor system comprising such sensor device and a magnet, optionally connected to a joystick.