A magnetic sensor device includes a magnetic sensor detecting a detection-target magnetic field, and a soft magnetic structure near the sensor. In an orthogonal coordinate system having two orthogonal axes for representing an applied field strength and a magnetization-corresponding value, coordinates representing the applied field strength and the magnetization-corresponding value move along a minor loop not in contact with a major loop as the strength of an external magnetic field including the detection-target magnetic field varies within a variable range, where the applied field strength is a strength of a magnetic field applied to the soft magnetic structure, the magnetization-corresponding value is a value corresponding to magnetization of the soft magnetic structure, and the major loop is, among loops traced by a path of the coordinates as the applied field strength is varied, a loop that is the largest in terms of area of the region enclosed by the loop.

A magnetic sensor device includes a magnetic sensor detecting a detection-target magnetic field, and a soft magnetic structure near the sensor. In an orthogonal coordinate system having two orthogonal axes for representing an applied field strength and a magnetization-corresponding value, coordinates representing the applied field strength and the magnetization-corresponding value move along a minor loop not in contact with a major loop as the strength of an external magnetic field including the detection-target magnetic field varies within a variable range, where the applied field strength is a strength of a magnetic field applied to the soft magnetic structure, the magnetization-corresponding value is a value corresponding to magnetization of the soft magnetic structure, and the major loop is, among loops traced by a path of the coordinates as the applied field strength is varied, a loop that is the largest in terms of area of the region enclosed by the loop.

A method of determining a configuration of a measurement volume, the method may include: generating, by at least one transmitter, a transmitted magnetic field within the measurement volume; measuring, by at least one receiver positioned, a total magnetic field in the measurement volume at at least one receiver position and generating at least one receiver output signal; generating, by a processing unit, a measured dataset; comparing, by the processing unit, the measured dataset with at least one of at least two reference configuration datasets each for determined for one of at least two different configurations of the measurement volume; and identifying, by the processing unit, a reference configuration dataset of the at least two reference configuration datasets that corresponds to the measured dataset.

A differential gradiometer comprising a substrate with at least a pair of resonators disposed thereon, wherein each of the at least a pair of resonators is sensitive to environmental factors which produces differential strains between the resonators, a first one of said pair of resonators being connected with a circuit for forming a first oscillator, the second one of said pair of resonators being connected with another circuit for forming a non-linear oscillator, an output of the first oscillator being applied to the non-linear oscillator for generating a comb of frequencies, wherein an addition oscillator is locked to the nth tooth of the comb thereby increasing the sensitivity of the gradiometer by a factor of n.

A differential gradiometer comprising a substrate with at least a pair of resonators disposed thereon, wherein each of the at least a pair of resonators is sensitive to environmental factors which produces differential strains between the resonators, a first one of said pair of resonators being connected with a circuit for forming a first oscillator, the second one of said pair of resonators being connected with another circuit for forming a non-linear oscillator, an output of the first oscillator being applied to the non-linear oscillator for generating a comb of frequencies, wherein an addition oscillator is locked to the nth tooth of the comb thereby increasing the sensitivity of the gradiometer by a factor of n.

A method of determining a gradient of a magnetic field, includes the steps of: biasing a first/second magnetic sensor with a first/second biasing signal; measuring and amplifying a first/second magnetic sensor signal; measuring a temperature and/or a stress difference; adjusting at least one of: the second biasing signal, the second amplifier gain, the amplified and digitized second sensor value using a predefined function f(T) or f(T, ΔΣ) or f(ΔΣ) of the measured temperature and/or the measured differential stress before determining a difference between the first/second signal/value derived from the first/second sensor signal. A magnetic sensor device is configured for performing this method, as well as a current sensor device, and a position sensor device.

A method of determining a gradient of a magnetic field, includes the steps of: biasing a first/second magnetic sensor with a first/second biasing signal; measuring and amplifying a first/second magnetic sensor signal; measuring a temperature and/or a stress difference; adjusting at least one of: the second biasing signal, the second amplifier gain, the amplified and digitized second sensor value using a predefined function f(T) or f(T, ΔΣ) or f(ΔΣ) of the measured temperature and/or the measured differential stress before determining a difference between the first/second signal/value derived from the first/second sensor signal. A magnetic sensor device is configured for performing this method, as well as a current sensor device, and a position sensor device.

Disclosed is an inverse estimation-based radius calculation method and system for ferromagnetic target detection. The calculation method includes a data acquisition step and a ferromagnetic target detection radius calculation step. Distrubance of a scale model to power frequency electromagnetic waves is used to inversely estimate a corresponding ferromagnetic target detection radius. Inverse estimation is performed separately for an air layer and a sea water layer according to test results of multiple scale model tests and in consideration of both a stationary state and a motion state of the scale model, so as to acquire a ferromagnetic target detection radius calculation formula. Weights of factors such as mass, speed, depth, and height are great in inverse estimation, so that inverse estimation precision is improved. The majority of background noise interference can be screened out of the power frequency electromagnetic waves.

Disclosed is an inverse estimation-based radius calculation method and system for ferromagnetic target detection. The calculation method includes a data acquisition step and a ferromagnetic target detection radius calculation step. Distrubance of a scale model to power frequency electromagnetic waves is used to inversely estimate a corresponding ferromagnetic target detection radius. Inverse estimation is performed separately for an air layer and a sea water layer according to test results of multiple scale model tests and in consideration of both a stationary state and a motion state of the scale model, so as to acquire a ferromagnetic target detection radius calculation formula. Weights of factors such as mass, speed, depth, and height are great in inverse estimation, so that inverse estimation precision is improved. The majority of background noise interference can be screened out of the power frequency electromagnetic waves.

A magnetic sensor system includes two magnetic sensors that detect components in two directions of an external magnetic field, an additional magnetic field generation section, and a signal processing circuit. The additional magnetic field generation section is capable of generating two additional magnetic fields for use in measuring the sensitivities of the two magnetic sensors. The signal processing circuit includes a sensitivity measurement processing section and a detection signal correction processing section. The sensitivity measurement processing section measures the sensitivities based on data concerning changes in the detection signals of the two magnetic sensors when the additional magnetic field generation section is controlled to generate two additional magnetic fields. The detection signal correction processing section performs processing for reducing change components attributable to the two additional magnetic fields on the detection signals of the two magnetic sensors.