273results about "Electrodynamic magnetometers" patented technology

A magnetic anomaly surveillance system includes triaxial magnetometer (TM) sensors arranged at known locations in an array. A processor coupled to the TM sensors generates a scalar magnitude of a magnetic anomaly field measured at each of the TM sensors. The scalar magnitude is indicative of a spherical radius centered at the known location associated with a corresponding one of the TM sensors. The processor also generates a comparison between each scalar magnitude and a threshold value. The processor then determines at least one magnetic anomaly location in the coordinate system via a spherical trilateration process that uses each spherical radius and each scalar magnitude associated with selected ones of the TM sensors for which the threshold value is exceeded. One or more output devices coupled to the processor output data indicative of the one or more magnetic anomaly locations.

A micro-electromechanical system (MEMS) based current & magnetic field sensor includes a MEMS-based magnetic field sensing component having a capacitive magneto-MEMS component, a compensator and an output component for sensing magnetic fields and for providing, in response thereto, an indication of the current present in a respective conductor to be measured. In one embodiment, first and second mechanical sense components are electrically conductive and operate to sense a change in a capacitance between the mechanical sense components in response to a mechanical indicator from a magnetic-to-mechanical converter.

A magnetic field measurement system includes an array of magnetometers; at least one magnetic field generator with each of the at least one magnetic field generator configured to generate a first magnetic field at one or more of the magnetometers, wherein the generated first magnetic field combines with the ambient magnetic field to produce a directional magnetic field at the one or more of the magnetometers, where a magnitude and direction of the directional magnetic field is selectable using the at least one magnetic field generator; and a controller coupled to the magnetometers and the at least one magnetic field generator, the controller including a processor configured for receiving signals from the magnetometers, observing or measuring a magnetic field from the received signals, and controlling the at least one magnetic field generator to generate the first magnetic field and select the direction of the directional magnetic field.

A MEMS magnetometer comprises a deflectable resonator comprising a base layer; a Lorentz force (LF) drive conductor attached to the base layer; and a piezoelectric sensor attached to the base layer and electrically isolated from the LF drive conductor. The LF drive conductor comprises conductive material configured for receiving a current at a mechanical resonant frequency of the device capable of causing mechanical deformation of the deflectable resonator, wherein the current causes formation of Lorentz forces in a presence of a magnetic field, and wherein the deflectable resonator is mechanically deformed as a result of the formation of the Lorentz forces. The mechanical deformation of the deflectable resonator generates a detectable piezoelectric electrical signal that is proportional to the magnitude of the magnetic field.

One embodiment is a magnetic field measurement system that includes at least one magnetometer having a vapor cell, a light source to direct light through the vapor cell, and a detector to receive light directed through the vapor cell; at least one magnetic field generator disposed adjacent the vapor cell; and a feedback circuit coupled to the at least one magnetic field generator and the detector of the at least one magnetometer. The feedback circuit includes at least one feedback loop that includes a first low pass filter with a first cutoff frequency. The feedback circuit is configured to compensate for magnetic field variations having a frequency lower than the first cutoff frequency. The first low pass filter rejects magnetic field variations having a frequency higher than the first cutoff frequency and provides the rejected magnetic field variations for measurement as an output of the feedback circuit.

A method for generating alkali metal in a zero oxidation state includes reacting an alkali metal compound having a —S-M substituent, where M is an alkali metal and S is sulfur, with gold in a zero oxidation state to release the alkali metal in the zero oxidation state. For example, an alkali metal alkylthiolate can be reacted with a gold in a zero oxidation state to release the alkali metal in the zero oxidation state. As another example, an alkali metal sulfide can be reacted with gold in a zero oxidation state to release the alkali metal in the zero oxidation state. The alkali metal may be used in various applications including vapor cells, magnetometers, and magnetic field measurement systems.

The present invention discloses a triaxial magnetoresistive sensor. It comprises a substrate integrated with a biaxial magnetic field sensor, a Z-axis sensor that has a sensing direction along Z-axis perpendicular to the two axes of the biaxial magnetic field sensor, and an ASIC. The biaxial magnetic field sensor comprises an X-axis bridge sensor and a Y-axis bridge sensor. The Z-axis sensor and the two-axis sensor are electrically interconnected with the ASIC. A single-chip implementation of the triaxial magnetic field sensor comprises a substrate, onto which a triaxial magnetic field sensor and an ASIC are stacked. The triaxial magnetic field sensor comprises an X-axis bridge sensor, a Y-axis bridge sensor, and a Z-axis bridge sensor. The above design provides a highly integrated sensor with high sensitivity, low power consumption, good linearity, wide dynamic range, excellent thermal stability, and low magnetic noise.

A system comprises an inertial measurement unit comprising one or more gyroscopes configured to measure angular velocity about a respective one of three independent axes and one or more accelerometers configured to measure specific force along a respective one of the three independent axes; a magnetometer configured to measure strength of a local magnetic field along each of the three independent axes; and a processing device coupled to the inertial measurement unit and the magnetometer; the processing device configured to compute kinematic state data for the system based on measurements received from the magnetometer and the inertial measurement unit. The processing device is further configured to calculate magnetometer measurement calibration parameters using a first technique when position data is unavailable and to calculate magnetometer measurement calibration parameters using a second technique when position data is available.

A microelectromechanical modulating magnetic sensor comprising a base; a magnetic transducer associated with the base that provides an output in response to a magnetic field; a pair of movable flux concentrators positioned to move relative to the magnetic transducer; the pair of movable flux concentrators having a region of high flux concentration between the pair of movable flux concentrators; the pair of flux concentrators moving together in tandem with the distance between the pair remaining substantially constant during movement; support structure for supporting the pair of movable flux concentrators; a power source for causing the movable flux concentrators to move at a frequency within a predetermined frequency range; whereby when the pair of movable flux concentrators is in a first position the region of high flux concentration is in a first location, and when the pair of movable flux concentrators is in a second position, the region of high flux concentration is in a second position; such that as the flux concentrators move from the first position to the second position the intensity of the flux sensed by the transducer is modulated as the region of high flux concentration approaches and recedes from the location of the transducer.

A gradient sensor of a component of a magnetic field comprising at least one elementary sensor comprising a deformable mass (31) equipped with a permanent magnet (32) having a magnetization direction substantially colinear to the direction of the gradient of the component of the magnetic field to be acquired by the sensor. The deformable mass (31) is able to deform under the effect of a force exerted on the magnet by the gradient, the effect of this force being to shift it, by dragging the deformable mass (31), in a direction substantially colinear to the component of the magnetic field for which the sensor has to acquire the gradient. The deformable mass (31) is anchored to a fixed support device (33) in at least two anchoring points (36) substantially opposite relative to the mass (31). The elementary sensor also comprises measuring means (35, 35.1, 35.2, 35.3) of at least one electric variable translating deformation or stress of the deformable mass (31) engendered by the gradient.

A sensor element, in particular for determining an angle of rotation, has a detection medium whose position varies as a function of a change in a parameter to be measured, where the change in the position of the detection medium leads to a change in an analyzable signal of the sensor element which is influenced by the detection medium. The detection medium has at least one conductor loop carrying current which is exposed to an external magnetic field; the detection medium is rotationally movably mounted so that a rotational motion of the sensor element about an angle of rotation in the plane of the magnetic field is converted into a deflection of the detection medium perpendicular to the magnetic field.

A rotating concave eddy current probe for detecting fatigue cracks hidden from view underneath the head of a raised head fastener, such as a buttonhead-type rivet, used to join together structural skins, such as aluminum aircraft skins. The probe has a recessed concave dimple in its bottom surface that closely conforms to the shape of the raised head. The concave dimple holds the probe in good alignment on top of the rivet while the probe is rotated around the rivet's centerline. One or more magnetic coils are rigidly embedded within the probe's cylindrical body, which is made of a non-conducting material. This design overcomes the inspection impediment associated with widely varying conductivity in fastened joints.

An array of induction magnetometers for use in airborne transient electromagnetic (ATEM) geophysical exploration is disclosed, having similar weight and external dimensions of prior art induction magnetometers but with improved signal strength, signal-to-noise ratio, higher frequency, self-resonance and bandwidth, and providing accurate and well monitored calibration.

The invention provides a micro machinery magnetic field sensor and a preparation method thereof, which belong to the field of a micro electro mechanical system. A sacrifice layer with a contact hole is deposited on a structural layer of a device, a metal coil is prepared on the sacrifice layer, then the sacrifice layer is corroded, and finally dry etching is used to manufacture a device structure, and the device structure is released to form a resonance oscillator so as to form the metal coil to hang on the micro machinery magnetic field sensor above the resonance oscillator. The resonance oscillator of the micro machinery magnetic field sensor works in an extension module, so that induced electromotive force produced by each small section of metal cutting magnetic induction lines on the metal coil can be overlapped, strength of output signals is strengthened, and contact surface between the metal coil and the resonance oscillator is reduced to solve the problem of signal crosstalk in high frequency. In addition, the micro machinery magnetic field sensor has the advantages of being low in power consumption, simple in driving-detection circuit, small in temperature influence, simple in process and the like.

A magnetometer and concomitant magnetometry method comprising emitting light from a light source, via a pulse generator pulsing light from the light source, directing the pulsed light to an atomic chamber, employing a field sensor in the atomic chamber, and via a signal processing module receiving a signal from the field sensor.

The resonator-based magnetic field sensor system has an oscillatory member as resonator, means for driving an electrical current through said resonator such that its resonance frequency is altered by an external magnetic field to be measured (measurand), and means for detecting or measuring said altered resonance frequency. A secondary excitation of the resonator is effected to determine the said altered resonance frequency from which the measurand can be deduced. In the preferred embodiment, the secondary excitation is included in a closed loop, thus creating an oscillator vibrating at the altered resonance frequency. Though it is known to use the oscillation amplitude of a suitable resonator for this purpose, the novel sensor system identifies and/or measures the frequency (not the amplitude) of the oscillation, which is a function of the magnetic field to be measured.

The invention discloses a fiscal electricity meter for measuring energy supplied to a load. The load current flows through the primary coil of a sensor and induces an EMF (Electromotive Force) that can represent the current flowing in the secondary coil. The secondary coil includes a sensing winding arranged to couple more strongly to the primary coil and a canceling compensation winding having the same and opposite multi-turn conductor areas so as to provide an inactive response to an external magnetic field. The windings are arranged so that their magnetic axes are coaxial and aligned so that they also provide ineffective response to external magnetic fields with field gradients.

The invention provides a micro-mechanical magnetic field sensor and a preparation method thereof and belongs to the field of micro-electro-mechanical systems. The method comprises the following steps of: manufacturing metal coils and a pad on a device structure layer; manufacturing a device structure by dry etching; and releasing the device structure to form a harmonic oscillator. The harmonic oscillator of the micro-mechanical magnetic field sensor provided by the invention operates in an extension mode, so induced electromotive force which is generated by each section of metal cutting magnetic induction line on each metal coil can be superposed, and the intensity of an output signal is improved. Moreover, the micro-mechanical magnetic field sensor has the advantages of low power consumption, simple driving/detection circuit, simple process, high industrial value and the like and is slightly influenced by temperature.

A method for measuring current in an electric network comprising at least one first electric line. The method includes fitting the first line with a circuit breaker having a protection coil and having a wall traversed by a magnetic field emitted by the protection coil; arranging on the wall of the circuit breaker a synchronous three-axis digital magnetometer on a semiconductor chip; by way of the digital magnetometer, measuring at least one component of a magnetic field emitted by the coil; and determining the value of a current traversing the electric line from the measured component.

A detecting device includes a reading coil configured to read a magnetic flux generated by a detecting coil for detecting a magnetic field of an electromagnetic wave output from an exciting coil according to the magnetic field. The detecting device further includes a Q-value measuring section configured to measure a Q-value of the detecting coil on a basis of a temporal transition of oscillation of a voltage obtained in the reading coil according to the magnetic flux generated by the detecting coil.

According to some embodiments of the present invention, a magnetometer includes at least one sensor for sensing a magnetic field component, a biasing circuit, and a processor. The sensor generates an output signal having a signal characteristic that varies in response to the sensed magnetic field component and in response to an applied bias. The biasing circuit dynamically biases the sensor in response to a bias setting signal. The processor is coupled to receive the output signal from the sensor and coupled to the biasing circuit. The processor is operable to generate the bias setting signal and thereby control the biasing circuit to dynamically bias the sensor such that the signal characteristic of the output signal is maintained in a target range. The processor determines the magnetic field component sensed by the sensor as a function of the bias setting applied to the sensor.

A magnetic field sensor that can be manufactured using the technology of surface micromechanics, having a conductor loop that has at least one deformable segment; a deformation device for deforming the deformable segment of the conductor loop with a predeterminable time dependence; a voltage sensing device for sensing the voltage induced at the ends of the conductor loop upon deformation in the presence of a magnetic field; and a magnetic field determining device for determining the present static and/or dynamic magnetic field in consideration of at least the time dependence of the deformation.

The invention provides a micromechanical magnetic field sensor and application thereof. The micromechanical magnetic field sensor at least comprises a resonant vibrator pair and insulating layers and metal coils, which are formed on the surface of the resonant vibrator pair in sequence. The micromechanical magnetic field sensor has the following beneficial effects: the micromechanical magnetic field sensor utilizes differential capacitor excitation and electromagnetic induction to measure the size of a magnetic field, wherein two resonant vibrator structures forming the resonant vibrator pair work in an inverse phase mode, the winding directions of the metal coils on the resonant vibrator structures are opposite, and the induced electromotive forces generated by the metal coils on the two resonant vibrator structures are connected with each other in parallel; as driving signals are differential signals, capacitive coupling signals in output signals are eliminated to obtain simple magnetic field output signals; meanwhile, the two resonant vibrator structures are coupled by a coupling structure so that the two resonant vibrator structures are connected and move as a whole; and furthermore, the micromechanical magnetic field sensor has simple structure, large output signals, high sensitivity and high detection accuracy, is slightly affected by temperature and is suitable for high working frequency.