192results 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).

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.

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 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 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 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.

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.

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.

The invention provides a single-axis magnetic gradient detection method and system based on an active attitude, and relates to the field of single-axis magnetic gradient detection.The method comprises the steps that the attitude of a carrier is adjusted according to the magnetic gradient detection requirement; acquiring magnetic gradient information, position information of a carrier and attitude information of the carrier; constructing an inversion equation of active attitude single-axis magnetic gradient detection data; and obtaining three-dimensional magnetic distribution of the detection space by combining the magnetic gradient information, the position information and the attitude information with an inversion equation. According to the technical scheme, a solution can be provided for single-axis magnetic gradient detection of the dynamic load platform, and the detection efficiency and the detection precision are effectively improved by actively utilizing the attitude change information.

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 discloses a high-voltage cable sheath circulating current monitoring device and a fault positioning method, and particularly relates to the technical field of cable fault monitoring. Comprising a distributed optical fiber sensor spirally wound on the surface of a cable, quantum magnetometer array modules arranged at equal phase difference of 90 degrees, a climbing robot used for positioning and clamping, and an edge calculation module integrated with an improved WP-CNN processing chip. The fault positioning method is realized by acquiring a magnetic field gradient tensor, constructing a fault feature vector, performing wavelet packet decomposition, performing convolutional neural network operation, calculating a fault point distance, and finally moving and clamping and fixing a fault point by a climbing robot. The cable state can be accurately monitored, fault features can be efficiently extracted, fault positioning can be accurately carried out, fault processing and continuous monitoring are facilitated, and safe and stable operation of the high-voltage cable is effectively guaranteed.

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.

To provide a method, a sensor device and a current measuring system for determining a current flowing in a conductor.SOLUTION: A method includes the steps of: providing a plurality of magnetic sensor elements sensitive to a magnetic field (B) generated by a current to sensor positions relative to a predetermined reference point, respectively; outputting a sensor signal indicating characteristics of the magnetic field at each sensor position; receiving the sensor signal by a processing circuit; mapping the received sensor signal to an output value indicating a current; and outputting the output value. The step of mapping includes the use of multipole development of the magnetic field generated by the current, and the multipole development includes the predetermined number of predetermined multipole components and respectively related predetermined multipole coefficients.SELECTED DRAWING: Figure 1

The present invention relates to a magnetic field gradient (B a -B b The present invention relates to a magnetic field gradiometer (1) for determining the magnetic field gradiometer (1), comprising at least one excitation light source (5a, 5b) for emitting excitation light (6a, 6b), two spatially spaced measurement areas (3a, 3b) for measuring the magnetic field, each having color centers in diamond, preferably NV centers (4a, 4b) that emit fluorescent light (7a, 7b) when excited by the excitation light (6a, 6b), and a first detector (3a) for detecting the fluorescent light (7a) from the first measurement area (3a). (8a), a second detector (8b) for detecting fluorescent light (7b) from the second measurement area (3b), a first microwave radiator (10a) for applying a first microwave field (9a) to the first measurement area (3a), a second microwave radiator (10b) for applying a second microwave field (9b) to the second measurement area (3b), and a magnetic field gradient (B) based on the fluorescent light (7a) detected from the first measurement area (3a) and the fluorescent light (7b) detected from the second measurement area (3b). a -B b The magnetic field gradiometer (1) comprises an evaluation device (11) configured to determine a first microwave signal (f MW1 (t)) for the second microwave radiating portion (10b), and a second microwave signal (f MW2 (t)) and a signal generator (12) configured to generate a

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.