A device with position detection includes: a first hall element; a second hall element; a differential amplifier configured to generate a subtraction voltage by differentially amplifying a first hall voltage generated by the first hall element and a second hall voltage generated by the second hall element; a summing amplifier configured to generate a sum voltage by summatively amplifying the first and second hall voltages; a comparer configured to compare a reference voltage with the subtraction voltage to generate an error voltage; and a current converter configured to generate a bias current provided to the first and second hall elements, based on the error voltage, wherein the device is configured to detect a position of a detection object based on the sum voltage.

A calibration system for a magnetometer having an unknown gain is disclosed. A calibration magnetic field is generated at a calibration frequency of a known amplitude at the magnetometer. A measurement of the calibrating magnetic field is reported by the magnetometer. A ratio of an amplitude of the calibration magnetic field measurement reported by the magnetometer and the known amplitude of the calibrating magnetic field at the magnetometer is computed. The unknown gain of the magnetometer is determined at least partially based on computed ratio.

Provided is a magnetic field measuring apparatus for: acquiring the measurement data measured by a magnetic sensor array that is configured by arraying the plurality of magnetic sensor cells to form a surface covering at least a part of a target object to be measured; performing signal separation on a magnetic field spatial distribution indicated by the measurement data based on a position and magnetic sensitivity of each magnetic sensor; generating a calibration magnetic field at a position on a straight line that can be drawn without crossing the plurality of magnetic sensor cells from the measurement space outside the measurement space; and calibrating a sensor error for the magnetic sensor based on a separation error in a case where signal separation has been performed on a spatial distribution of the calibration magnetic field.

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 linear or angular position of a magnetic sensor device relative to a magnetic source, or vice versa, the sensor device includes at least four magnetic sensor elements. The method involves the steps of: a) determining a first magnetic field gradient; b) determining a second magnetic field gradient; c) determining a ratio of the first and second magnetic field gradient; d) converting the ratio into a position; while matching signal paths of the magnetic sensor elements so as to improve signal-to-noise.

In one aspect, an angle sensor includes a first Hall element disposed on a first axis, a second Hall element disposed on a second axis perpendicular to the first axis and a conduction path having a first portion extending parallel to the first axis and a second portion parallel to the second axis. The conduction path is configured to conduct a calibration current that generates a first magnetic flux density measured at the first Hall element and a second magnetic flux density measured at the second Hall element. The angle sensor also includes calibration circuitry configured to generate one or more compensation signals based on the first and second magnetic flux densities and to adjust an external magnetic flux density measured at the second Hall element due to an external magnetic field using the one or more compensation signals to reduce angle error of the angle sensor.

The present invention relates to a hall electromotive force signal detection circuit and a current sensor thereof each of which is able to achieve excellent wide-band characteristics and fast response as well as high accuracy. A difference calculation circuit samples a component synchronous with a chopper clock generated by a chopper clock generation circuit, out of an output voltage signal of a signal amplifier circuit, at a timing obtained from the chopper clock, so as to detect the component. An integrating circuit integrates an output from the difference calculation circuit in the time domain. An output voltage signal from the integrating circuit is fed back to a signal amplifier circuit via a third transconductance element.

Systems and methods may provide for obtaining first sensor data associated with a gyroscope and obtaining second sensor data associated with a magnetometer. Additionally, the first sensor data, the second sensor data and an extended Kalman filter may be used to calibrate the magnetometer. In one example, a sampling rate of the magnetometer is increased before obtaining the second sensor data and the sampling rate of the magnetometer is decreased after calibration of the magnetometer.

A method of calibrating a network of magnetometers (C1, Ci) including the displacement of a magnet holder tool (10) above the network, and solving an optimisation problem to determine a localisation of the magnetometers in the network. This localisation minimises based on an optimisation criterion, the difference between a real attribute (D, m1, m2) of the magnet holder tool and an estimate of the attribute determined without knowledge of the displacement, starting from the localisation and measurements made by the magnetometers in the network during the displacement.

Systems and methods are disclosed for generating a magnetic fingerprint map. Information representing orientation and position of each portable device is obtained along with magnetic field measurements that are correlated with positions determined from the information. Uncertainties associated with the magnetic field measurements are estimated and the magnetic field measurements and associated uncertainties are converted from a device frame to a unified fingerprint frame using the orientations determined from the information. Parameters of a probability distribution function for magnetic field measurements and contaminating measurements are mitigated at each determined position based at least in part on the converted magnetic field measurements and associated uncertainties. Correspondingly, the magnetic fingerprint map is generated from the determined parameters of the probability distribution functions.