Magnetic field components are measured at multiple longitudinal positions and used to calculate estimated longitudinal position and length of a transversely localized electric current segment flowing across a gap between conductive bodies. The apparatus can be used with a remelting furnace. The electrode and ingot act as the conductive bodies, and arcs, discharges, or slag currents are the current segments spanning the gap. Actuators for movable sensors can be coupled to the sensors in a servomechanism arrangement to move the sensors along with the moving gap. An actuator for moving one of the conductive bodies can be coupled to sensors in a servomechanism arrangement to maintain the gap distance within a selected range as the gap moves.

A receiver for detecting at least one electromagnetic signal while the receiver is moving relative to the Earth's magnetic field, the receiver comprising: an SQUID array for generating an output that is a transfer function of SQUID array magnetic flux that is supplied from a combination of an oscillating magnetic field of the at least one electromagnetic signal, the Earth's magnetic field, and a bias magnetic field; a bias-tee configured to divide the SQUID array output into a DC signal and an RF signal; a memory store configured to store a plurality of voltage and flux bias values, wherein each voltage value has a corresponding flux bias value that results in maximum SQUID array sensitivity; and a logic circuit configured to find a voltage value in the memory store that most closely matches the DC signal, and to apply to the SQUID array a flux bias corresponding to the most closely matched voltage value.

Disclosed herein are systems and methods for a three-dimensional (3D) non-contact position sensor. A system includes a magnetic target coupled to and/or integrated with a target object and a position sensor comprising a plurality of magnetometers configured to provide a set of magnetic flux values corresponding to a magnetic field generated by the magnetic target. A logic device receives the set of magnetic flux values provided by the plurality of magnetometers of the position sensor and determines a position and/or orientation of the target object based, at least in part, on the received set of magnetic flux values. The position and/or orientation of the target object may be used as feedback to help position and/or orient the target object according to a desired position and/or orientation or to track its position accurately in real-time.

A computer-implemented method includes, by one or more processors in electronic communication with a tunneling magnetoresistive sensor, wherein the tunneling magnetoresistive sensor is a component of a magnetic storage drive configured to read magnetic data from a magnetic storage medium, detecting a short across the tunneling magnetoresistive sensor, measuring a change in resistance of the tunneling magnetoresistive sensor, measuring a change in voltage amplitude for the tunneling magnetoresistive sensor, and dividing said change in voltage amplitude by said change in resistance to yield a ratio. The computer-implemented method further includes, responsive to the ratio being greater than a predetermined ratio threshold, determining that the short is caused by a magnetic shunt. A corresponding computer program product and computer system are also disclosed.

A Hall sensor is disclosed. The Hall sensor comprises a first Hall element, configured to detect a component of a magnetic field in a first direction a using a sensitive area of the first Hall element. The Hall sensor further comprises a second Hall element, configured to detect a component of the magnetic field in a second direction b using a sensitive area of the second Hall element. The Hall sensor further comprises a conductor track, configured to generate a calibration magnetic field. The calibration magnetic field has a significant component on the sensitive area of the first Hall element in the second direction b. The calibration magnetic field further has a significant component on the sensitive area of the second Hall element in the first direction a.

The innovative concept described herein relates to a sensor chip having at least two magnetic field sensors that are arranged adjacently to one another on the sensor chip and measure perpendicularly to the chip plane, wherein at least one of the magnetic field sensors has a planar coil arranged on it that is configured to generate a magnetic field directed perpendicularly to the chip plane. A controller is able to operate the magnetic field sensors in a calibration mode, in which the planar coil generates the magnetic field. For the purpose of calibrating the magnetic field sensors, a differential measurement may be taken that involves the response signal from one magnetic field sensor being subtracted from the response signal from the other magnetic field sensor.

Methods and apparatus for a magnetic sensor having a die and sensor circuitry formed in a device layer of the die with a coil integrated with the die to generate a magnetic field. A magnetoresistive magnetic field sensing element on the die detects changes in the magnetic field generated by the coil as a result of the presence of a ferromagnetic target. The sensor circuitry may process the changes in the magnetic field generated by the coil.

A magnetic field sensor includes at least one magnetic field sensing element configured to generate a measured magnetic field signal responsive to an external magnetic field and to generate a reference magnetic field signal responsive to a reference magnetic field and a calibration circuit configured to divide the measured magnetic field signal by the reference magnetic field signal to generate a calibrated magnetic field signal. The calibrated signal has reduced susceptibility to stress influences.

Embodiments are disclosed for various configurations of a hybrid Hall/MR magnetometer with self-calibration. In an embodiment, a method comprises: a circuit coupled to a magnetometer and configured to determine whether the magnetometer is to operate in a sensing operation mode or a self-calibration operation mode. The magnetometer comprises a Hall sensor and MR sensor coupled to the circuit. In accordance with determining a sensing operation mode, the Hall sensor is turned and the MR sensor is turned on; and an external magnetic field is measured using the MR sensor. The magnetic field measurement is calibrated using a MR sensor bias error determined in a self-calibration operation mode of the sensor.

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.