147results 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).

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.

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 relates to the technical field of particle size analysis, solves the technical problem of signal distortion in rodlike abrasive dust particle size monitoring in a high-intensity magnetic field environment, and particularly relates to an inverse Fourier transform particle cross detection method and system for a laser particle analyzer, and the method comprises the following steps: collecting an original scattered light intensity signal and magnetic field intensity data; calculating a magnetic field change gradient based on the magnetic field intensity data; calculating a predicted phase offset used for eliminating signal distortion caused by rotating speed abrupt change by using the magnetic field change gradient; and identifying an oscillation risk period based on the magnetic field change gradient and a preset risk determination threshold. The method breaks through the hypothesis of a traditional Mie theory on spherical particles, establishes a scattering kernel function of the rod-shaped particles based on a T matrix theory, introduces a magnetic field coupling term, and quantifies the influence of a magnetic field on particle orientation and scattering signals. The situation that single particles are misjudged as multi-size mixed particles due to scattering double-peak artifacts caused by directional arrangement of the rod-shaped particles in a high-intensity magnetic field is avoided, and the particle size inversion precision is remarkably improved.

Provided is a magnetic moment measurement system and method, which belong to the technical field of magnetic moment measurement, and solve the problems of insufficient accuracy, low efficiency, and vulnerability to disturbance from an external magnetic field in the existing magnetic moment measurement technique. The magnetic moment measurement method includes the following steps: acquiring a magnetic field vector and a magnetic gradient tensor at a center of a magnetic sensor array through the magnetic sensor array; calculating an angle of a magnetic moment vector; and according to the angle of the magnetic moment vector, selecting a corresponding magnetic moment inversion formula, and calculating the magnetic moment vector. By constructing the magnetic sensor array, and using the advanced inversion algorithm, this application not only significantly improves the magnetic moment measurement accuracy, but also greatly shortens the measurement cycle, simplifies the measurement system, and reduces the measurement error.

The invention relates to the field of magnetic field measurement and sensor error compensation, and provides a magnetic gradient tensor array double-stage calibration method based on direction regularization, which comprises the following steps: acquiring magnetic vector observation data under multiple attitudes; constructing a twelve-parameter error model for explicitly distinguishing an internal error of the sensor from an array attitude error; based on the model, establishing an optimization objective function considering both module value consistency and direction consistency; a two-stage optimization strategy based on a differential evolution algorithm is adopted, in the first stage, all parameters are estimated to achieve coarse calibration, and in the second stage, estimated array attitude error parameters are optimized on the basis of internal error parameters of a fixed sensor; and finally, correcting a magnetic vector observation value according to the estimated calibration parameter, and calculating a magnetic gradient tensor through a symmetric difference method. Under the condition that no external magnetic field reference is needed, the measurement precision is improved by correcting the magnetic vector observation value, the accuracy of magnetic gradient tensor calculation is finally guaranteed, and the method has good engineering adaptability and popularization prospects.

The invention discloses a magnetic target boundary recognition method and system based on a magnetic gradient tensor, and relates to the technical field of geophysical exploration and industrial nondestructive testing, and the method comprises the following steps: collecting spatial magnetic gradient tensor data through a magnetic gradient sensor array, and obtaining nine components of the magnetic gradient tensor; calculating the vertical guide modulus of the vertical component of the magnetic gradient tensor; calculating a Z-direction analysis signal ASAz and a vertical guide thereof; a boundary recognition amount is generated by a ratio operation, and a boundary position of the magnetic target is determined based on a maximum value position of the boundary recognition amount. According to the method, a vertical component derivative and analytic signal derivative dual-derivative coupling mechanism is combined for the first time, the limitation that a traditional method depends on a single parameter is overcome, the vertical component derivative accurately captures the change rate of the boundary in the vertical direction, and the analytic signal derivative effectively suppresses background noise.

The invention belongs to the technical field of magnetic field measurement and instruments, and relates to a magnetic gradient tensor field interpolation method under physical potential field constraint, which comprises the steps of establishing a Gaussian process model of a magnetic gradient tensor field, acquiring a magnetic potential core and performing hyper-parameter optimization. According to the method, multi-component interpolation and curving are fused into a unified Gaussian process regression framework, and the multi-component interpolation and the curving are subjected to potential field physical constraints in a unified manner; a complete potential field physical constraint is used, meanwhile, no-rotation and no-divergence constraints are met, and magnetic gradient tensor measurement data interpolation with measurement errors is more accurate and better in anti-interference capability; by introducing a complete physical constraint fusion Gaussian process regression framework, the magnetic gradient tensor interpolation precision and stability are improved. Based on the magnetic potential core, all magnetic gradient tensor components can be modeled at the same time in the joint probability model, physical constraints among the components are guaranteed, non-planar data which are distributed at will can be processed naturally based on a Gaussian process regression framework, and an additional potential field continuation step is not needed.

The invention belongs to the technical field of magnetic field detection, and discloses a cross-shaped variable baseline magnetic flux gate array and method for measuring a three-order magnetic gradient tensor. The cross-shaped variable baseline magnetic flux gate array comprises a cross-shaped array rack, each supporting arm is provided with a sliding groove with the length of 1, and a sensor is installed on each sliding groove in a clamped mode. A sensor is mounted at the central point of the cross array rack; the baseline distances d between the adjacent sensors are equal, and the sensors slide in the corresponding sliding grooves. According to the adjusting method, the baseline distance is adjusted through the sliding groove. According to the rotation correction method, the surrounding sensors are corrected through the middle sensor, the measurement precision is improved, the zero-order magnetic gradient tensor and the first-order magnetic gradient tensor at the position of each sensor and the second-order magnetic gradient tensor and the third-order magnetic gradient tensor at the position of the center sensor can be measured at the same time, rich target magnetic field information is obtained, and the measurement accuracy is improved. The engineering practical value is realized.

The invention relates to a single-vector magnetometer motion direction magnetic gradient anomaly detection method, which comprises the following steps: based on a single-sensor magnetic gradient measurement technology, obtaining an x-axis motion direction magnetic gradient signal through spatial sampling; preprocessing the magnetic gradient signal in the x-axis motion direction; presetting an orthogonal basis function of the magnetic gradient in the x-axis motion direction; and carrying out magnetic gradient anomaly detection on the preprocessed signal based on a preset orthogonal basis function. The method is superior to a traditional vertical motion directional array double-sensor column magnetic gradient anomaly OBF detection method under the conditions of low noise ratio and platform shaking, has the advantages of being high in real-time performance, low in cost, small in size and the like, and shows a good application prospect under the scenes of danger detection, explosion removal, intrusion monitoring and the like.

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.

The invention provides a sensor device and a sensor system for determining an orientation of a magnet. A sensor device for determining the orientation (alpha, beta, phi, psi) of a magnet pivotable about a reference point (Pref), the sensor device comprising: a semiconductor substrate (703) comprising first and second magnetic sensors (S1, S2) spaced apart in a first direction (X), each magnetic sensor being configured for measuring a first magnetic field component (Bx1, Bx2) oriented in the first direction (X); a second magnetic field component (Bx2) oriented in a second direction (Y) and a second magnetic field component (By1, By2) oriented in a second direction (Y); wherein the sensor device further comprises processing circuitry configured to: i) determine a first magnetic field gradient (dBx / dx); ii) determining a second magnetic field gradient (dBy / dx); iii) determining a first angle (alpha, psi) based on the first magnetic field gradient (dBx / dx); iv) determining a second angle (beta, phi) based on the second magnetic field gradient (dBy / dx). A sensor system includes the sensor device and the magnet.

Disclosed in the embodiments of the present invention is a magnetic tunnel junction signal isolator with electric shielding layer. In the isolator, a coil is located between a magnetic shielding layer and an electric shielding layer; the electric shielding layer is located between the coil and a magnetoresistive sensor, the magnetoresistive sensor is composed of a plurality of magnetic tunnel junctions that are connected in a series-parallel way. The two ends of the coil are electrically connected to a circuit having a first reference ground used to send a signal; a signal is sent from the magnetoresistive sensor to a receiving circuit connected to a second reference ground. The magnetic shielding layer is electrically connected to the first reference ground in a single-point or multi-point mode, or it is completely electrically isolated from the first reference ground. The electric shielding layer may instead be electrically connected to the second reference ground in a single-point or multi-point mode, or it may be completely electrically isolated from the second reference ground. Or, the electric shielding layer and magnetic shielding layer are respectively electrically connected to any potential or potentials between the first reference ground and the second reference ground in a single-point or multi-point mode. The embodiments of the present invention, prevent the electric field from corrupting the magnetoresistive sensor signal, as such solving the problem of interference and damage caused to a magnetic tunnel junction in the magnetoresistive sensor by the coil.

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 disclosure relates to a system for measuring electric and / or magnetic field of an object, the system comprising: an underwater vehicle comprising: a plurality of links (2a-2d) that are connected to one another by joint modules for generating a flexural motion of the underwater vehicle; wherein the flexural motion devices enable movement of the underwater vehicle and control of the orientation and / or location of the underwater vehicle, wherein the plurality of the links define a hull having a first end (4a) and a second end (4b); a sensor arrangement comprises: a first electrode (6a) mounted on the first end (4a) of the hull; a second electrode (6b) mounted on the second end (4b) of the hull; the first and the second electrode configured to measure electric field of an object, the electric field data sampled with sampling frequencies between 1 and 300 Hz; and / or a first single, 2-, or 3-axes magnetometers (7a) mounted inside the first end (4a) of the underwater vehicle; a second single, 2-, or 3-axes magnetometers (7b) mounted inside the second end (4b) of the underwater vehicle; the single, 2-, or 3-axes magnetometers configured to measure a magnetic field of the object, wherein distance and relative position between the first end of the hull and the second end of the hull is adjustable to enable measuring electric and / or magnetic field in one or more planes / directions. The disclosure further relates to a method of measuring electric and / or magnetic field of an object with an underwater vehicle.

The invention belongs to the technical field of water supply and drainage safety, and particularly relates to a method for recognizing interference signals of ferromagnetic objects around a water supply and drainage pipeline. Comprising the following steps: S1, collecting related data of on-site water supply and drainage pipelines; s2, carrying out interference-free magnetic signal collection on related pipelines; s3, magnetic signal collection is carried out on related pipelines when interference exists; s4, comparing and analyzing the magnetic signal data of the pipeline without interference and the magnetic gradient component signal characteristics of the pipeline in the X, Y and Z directions under the interference signal of the ferromagnetic interferent; s5, judging whether ferromagnetic substance interference exists or not according to the component change condition; and S6, finding out unknown pipeline interference data for verification, and analyzing whether the periphery of the pipeline is interfered by ferromagnetic substances or not by observing component change characteristics. The method has the beneficial effects that the position of an interference signal can be accurately identified, the influence of the interference signal on a pipeline detection signal is eliminated, the health state of the pipeline can be accurately judged, and unnecessary maintenance and intervention can be avoided, so that the maintenance cost is reduced.

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.

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 magnetic bumper system for vehicles includes a bumper, a magnet, a sensor, a processor, and a memory. The magnet selectively generates a first magnetic field. The sensor measures a voltage value of a detected magnetic field. The memory causes the system to generate the first magnetic field, and sense a first voltage value of the detected magnetic field. Upon encountering a second magnetic field, the system senses a second voltage value of the detected magnetic field, and determines a difference between the first and second voltage values of the detected magnetic field. If the difference indicates that the pole of the magnetic object nearest to the magnet is different from the first pole of the magnet, the system stops the magnet from generating the first magnetic field.

The utility model discloses a magnetic gradient measuring device based on three-component sensor, including supporting seat for supporting, main gear, first slide plate and driving gear, the upper end of main gear is engaged with linkage gear, and the left end of linkage gear is fixedly connected with limit plate, the upper side of the rear end of first slide plate is fixedly connected with hydraulic rod, and the upper side of the rear end of first slide plate is fixedly connected with the hydraulic rod. A second sliding plate is connected to a clamping groove in the inner side of the right end of the first sliding plate, a belt body is fixedly connected to the front end of the first sliding plate, and rack plates are connected to the upper end and the lower end of the driving gear in an engaged mode. According to the magnetic gradient measurement device based on the three-component sensor, magnetic gradient measurement can be carried out according to different angles of a measured object, the detection height of the three-component sensor can be increased, magnetic gradient detection can be carried out on objects with different heights, the three-component sensor can be prevented from shaking in the measurement process, and the measurement accuracy is improved. And the measured magnetic gradient data is not accurate.