263results about "Magnetic gradient measurements" patented technology

In one embodiment, a method includes accessing magnetic data from a magnetic-measurement device. The magnetic data corresponds to one or more locations of the magnetic-measurement device. The method includes accessing geofencing data corresponding to an area; comparing the magnetic data with the geofencing data; based on the comparison, determining that the locations correspond to the area; and, based on the determination, authenticating the magnetic-measurement device for access to one or more resources.

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).

A sensor unit for detecting brain current-induced magnetic fields in an unshielded environment has a plurality of gradiometer units configured for arrangement around a head of a user. Each gradiometer unit has two magnetometers which are arranged at a fixed distance from each other. Each magnetometer has a sensor medium and is configured to detect a magnetic field strength at a measurement location by reading a spin resonance in the sensor medium depending on the magnetic field strength. The sensor unit further includes at least one excitation light source for radiating light into the sensor media of the magnetometer. The sensor unit further incudes at least one signal processing unit for determining a magnetic field gradient at a gradiometer unit as a difference of the output signals of the two magnetometers of the gradiometer unit and for detecting a time course of the magnetic field gradient.

The invention discloses a full-tensor high-order magnetic field gradient sensing system and a use method, the full-tensor high-order magnetic field gradient sensing system comprises a magnetic field sensing probe, a non-metal directional support, a high-strength engineering plastic shell and a communication antenna, the magnetic field sensing probe comprises a pure wood support frame, 15 three-axis magnetic field sensors and a magnetic field acquisition processing communication module; the nine three-axis magnetic field sensors are distributed in an xy plane in a shape like a Chinese character'tian ', and the six three-axis magnetic field sensors are arranged in an xz plane in an upper row and a lower row. The magnetic field sensing probe is installed in the nonmetal directional support through the pure wood supporting frame, and the z-axis of the magnetic field sensing probe is always kept in a plumb downward mode. The plastic sealed shell is wrapped outside the directional support, and the communication antenna is covered on the shell. By adopting the full-tensor high-order magnetic field gradient sensing system and the full-tensor high-order magnetic field gradient sensing method, all first-order and second-order magnetic field gradient parameters can be obtained, so that accurate measurement is carried out.

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.

In one embodiment, a method includes generating navigation or localization information based on a combination of first data that are based on first measurements of a magnetic field by one or more magnetic sensors and second data that are based on second measurements by one or more other sensors. The method includes determining an anomalousness of a magnetic field and, based on the determined anomalousness of the magnetic field, at least temporarily adjusting a weight of the first measurements relative to the second measurements in the generation of the navigation or localization information.

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 provides an SQUID working parameter regulation and control device and method. The SQUID working parameter regulation and control device comprises an SQUID reading circuit used for detecting a magnetic signal; the reference magnetic sensor is used for collecting working environment magnetic field data and providing a modulation signal for an SQUID device in the SQUID reading circuit; the control module is connected to the output end of the SQUID reading circuit and the output end of the reference magnetic sensor, when parameters are regulated and controlled, a relation curve of the output voltage and the input magnetic flux is constructed based on the influence of modulation signals on the SQUID device, the working point slope of the relation curve of the output voltage and the input magnetic flux is calculated, and the working point slope of the relation curve of the output voltage and the input magnetic flux is calculated. And a control signal of the SQUID reading circuit is generated, so that the slope of the working point reaches the maximum value. According to the invention, the working point can be intelligently adjusted in application, and high-reliability and high-accuracy magnetic detection can be realized in a complex working 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.

A sensor device includes at least one integrated magnetic sensor structure having: a semiconductor substrate; a magnetic flux concentrator IMC disposed on top of the semiconductor substrate, the IMC having a predefined shape with an elongated portion extending in a first direction parallel to the substrate; a horizontal Hall element situated under a centre of the IMC; a processing circuit connected to said horizontal Hall element, and configured to provide a signal or a value indicative of at least one magnetic field gradient or a signal or value derived therefrom.

The invention relates to the technical field of magnetic field precision measurement, in particular to an atomic magnetic gradient measurement device and method. Comprising a host which is internally provided with a laser light source and a control circuit thereof, a data acquisition unit and a probe control unit; each probe comprises a polarizer, a collimating and focusing lens, an atomic gas chamber and a photoelectric detector; the laser light source generates frequency-stabilized laser, the laser is divided into a plurality of paths with equal light intensity through the light splitting device, and the plurality of paths of laser enter the plurality of probes through the optical fibers respectively; the magnetometer is provided with a plurality of probes which are completely homologous, laser homology, air chamber excitation homology, clock homology and signal synchronous processing are included, common-mode noise caused by a laser light source, a signal processing circuit and the environment of the magnetometer is reduced in a differential mode, and the magnetic field measurement sensitivity and the system anti-jamming capability are improved; therefore, the influence of geomagnetic diurnal variation and ambient noise on the quality of magnetic field measurement data can be effectively eliminated.

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 provides a transient electromagnetic near-surface target feature recognition system and method, and relates to the technical field of underground target recognition, and the method comprises the steps: arranging a measurement grid, collecting a response voltage component of each measurement point through a JPMD sensor, calculating a magnetic gradient tensor, generating a target position vector, building a global coordinate system, and carrying out the Gaussian-Newton algorithm, thereby achieving the feature recognition of a transient electromagnetic near-surface target. And determining a positioning result based on the actual detection value and the predicted value of the single dipole model. The length-width ratio of the target is obtained by decomposing the magnetic gradient tensor, the attenuation time coefficient is corrected in combination with the soil conductivity to judge the conductivity of the target, clustering analysis is carried out on the target to improve the classification accuracy, and finally, target recognition models are trained for different clusters to recognize the types of the targets in the clusters. And the real-time target is identified through the corresponding target identification model after being distributed to the cluster. According to the method, multi-measurement-point data are fused, and the positioning precision and the target recognition efficiency are improved.

The invention provides a spacecraft and a product magnetic field measurement method thereof, electronic equipment and a storage medium, and the method comprises the steps: arranging a product magnetometer sensor and a background magnetometer sensor in a test region, and taking background measurement values of first background magnetic field data and second background magnetic field data at the same moment in each direction as input; fitting coefficients of background measured values and product measured values at the same moment in each direction are obtained through linear regression, a linear regression equation in each direction is constructed, background magnetic field interference is calculated according to the linear regression equations, the background magnetic field interference is eliminated from product magnetic field data, and the real magnetic induction intensity of the spacecraft and the product of the spacecraft is obtained. And calculating the magnetic moment of the spacecraft and the product thereof according to the real magnetic induction intensity. Based on the above mode, the influence of environmental fluctuation on the magnetic measurement of the spacecraft is reduced, and the purpose of accurately calculating the magnetic moment of the spacecraft and the product thereof is achieved.

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.

Methods for magnetic data acquisition in marine environment in parallel with towed streamer seismic data acquisition is provided. A method includes attaching at least one magnetometer / magnetic sensor with a buoy and positioning the magnetometer / magnetic sensor outside “prop wash” zone and / or far from sail line of the vessel so that removing noises in the magnetic data caused by movement of magnetometer and any other means of turbulence. Further, the buoy is equipped with a power generator and battery box to be self-sufficient with power to operate the magnetometer / magnetic sensor, and further comprises a radio link that communicate and transfer radio signal from the buoy to the vessel.

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 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.

The invention relates to the technical field of robot navigation, in particular to a precise inspection method for an underground cavity and an inspection robot. The method comprises the following steps: acquiring spatial point cloud data, robot pose data and scene magnetic field data, and constructing a magnetic field model according to the scene magnetic field data to obtain a scene magnetic field model; obtaining interference characteristic data according to the scene magnetic field model and the spatial point cloud data; obtaining magnetic disturbance weight data according to the disturbance characteristic data and the robot pose data; performing fusion filtering on the spatial point cloud data and the robot pose data according to the magnetic disturbance weight data to obtain navigation optimization data; performing residual analysis on the spatial point cloud data and the robot pose data according to the navigation optimization data to obtain residual trend data; and performing dynamic compensation according to the residual trend data to obtain space optimization point cloud data and robot optimization pose data. The anti-interference capability and the environmental adaptability of the inspection robot are improved.

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.

Various embodiments disclosed herein comprise systems and methods to arrange magnetic field sensors. In some examples a magnetic field detection system comprises a sensor holder and magnetometers. The sensor holder mounts the magnetometers proximate to a magnetic field source that generates a magnetic field. The magnetometers measure the magnetic field in multiple directions. A first portion of the magnetometers measures a normal component of the magnetic field and a first tangential component of the magnetic field, and a second portion of the magnetometers measures the normal component of the magnetic field and a second tangential component of the magnetic field. The sensor holder distributes the first portion of the magnetometers and the second portion of the magnetometers, so the tangential components measured by neighboring ones of the magnetometers mounted to the sensor holder are orthogonal.

The invention discloses a ship far-field magnetic field inversion method based on magnetic gradient tensor. According to a traditional naval vessel magnetic field inversion method based on magnetic induction intensity, in the naval vessel magnetic field separation step, an additional sensor needs to be arranged for obtaining a reference background geomagnetic field, measurement errors are difficult to control, measurement data are inaccurate, and errors are generated during naval vessel far-field magnetic field inversion. According to the method, the magnetic gradient tensor is used as data for constructing the magnetic field model, a background geomagnetic field does not need to be measured, the measurement steps are simplified, and meanwhile inversion of the far-field magnetic field of the naval vessel has high accuracy. According to the method, the ship model is solved by using the MOAEMDE algorithm, control parameters of the algorithm can be adaptively adjusted, repeated manual parameter configuration according to different measurement environments is not needed, and the method is high in adaptability and convenient to use.

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.

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.

A magnetic field gradiometer includes two spatially spaced-apart measurement regions including color centers in a diamond, which emit fluorescence upon excitation by an excitation light, a first detector for detecting the fluorescence from a first measurement region, a second detector for detecting the fluorescence from a second measurement region, a first microwave emitter for applying a first microwave field to the first measurement region, a second microwave emitter for applying a second microwave field to the second measurement region, an evaluation device configured to determine a magnetic field gradient based on the detected fluorescence from the first and the second measurement regions, and a signal generator unit configured to generate a first and a second microwave signals for the first and the second microwave emitters, respectively. Each of the first and the second microwave signals includes two frequency components with a phase offset of π with respect to one another.

The present invention provides a superconducting quantum interference device magnetic plane gradiometer, a magnetic field detection method and system, including: a superconducting closed loop and two SQUIDs; the superconducting closed loop includes a gradient coil and two input coils; the gradient coil is wound by two induction coils of equal size and opposite winding directions, and the two induction coils are symmetrical about a first symmetry axis; the two input coils are equal in size and symmetrically arranged on both sides of the gradient coil along the first symmetry axis, and the two input coils are connected in series with the gradient coil; two SQUIDs are symmetrically arranged on both sides of the superconducting closed loop along the first symmetry axis, and are used to respectively sense the magnetic flux of the corresponding input coils and convert the magnetic flux into voltage. The present invention sets a fully symmetrical magnetic gradiometer, and through the mode switching of single-side independent operation and double-side joint operation, avoids the common mode influence brought by the introduction of an additional superconducting loop, effectively reduces the imbalance of the gradiometer, and improves the overall uniformity of the device.

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.