A radio frequency (RF) weak magnetic field detection sensor includes a ferromagnetic core, a pickup coil disposed to surround the ferromagnetic core, a substrate that includes an opening, a core pad connected to the ferromagnetic core and a coil pad connected to the pickup coil, and an insulating tube interposed between the ferromagnetic core and the pickup coil. The insulating tube includes a bobbin around which the pickup coil is wound, and a core hole formed to pass through the bobbin and configured to accommodate the ferromagnetic core.

A marker detection method in which a magnetic detection unit (11) of a vehicle side that includes a plurality of magnetic sensors arranged in a vehicle width direction is used to detect magnetic markers (10) that are laid in a road, the method executes detection of a center position in the vehicle width direction of a magnetic distribution that acts on the magnetic detection unit (11) and processing of an index representing a degree of a positional change of the center position when a vehicle (5) passes over the magnetic markers (10) to determine a possibility of the presence of magnetic generation sources that causes disturbance, thereby suppressing erroneous detection of the magnetic markers (10).

A marker detection device which detects a magnetic marker laid in a road by using a sensor unit in which a plurality of combinations of a magnetic sensor and a magnetic-field generation coil are arranged includes a storage part which stores characteristic information of each magnetic-field generation coil, an estimation part which estimates a magnetic differential value acting on the magnetic sensor due to a current differential value acting on the magnetic-field generation coil by referring to the characteristic information of each magnetic-field generation coil, and a calibration part which calibrates each magnetic sensor so as to enhance uniformity in sensitivity, which is a ratio between an output differential value of the magnetic sensor in accordance with a change of a current by the current differential value acting on the magnetic-field generation coil and the estimated magnetic differential value.

Provided are a magnetic marker and a magnetic marker detection system with a reduced magnetic force. The magnetic marker detection system (1S) in which magnetism generated from the magnetic marker (1) laid on a road surface (53) is detected by a magnetic sensor (2) attached to a vehicle's body floor (50) of a vehicle (5) is a system with the magnetic marker (1) and the magnetic sensor (2) in combination, the magnetic marker having a surface with a magnetic flux density equal to or smaller than 40 mT and the magnetic sensor using a magneto-impedance element including an amorphous wire as a magneto-sensitive body with impedance in a high-frequency region changing in accordance with an external magnetic field.

The invention relates to a three-dimensional magnetic field detection device (1) which comprises three soft-magnetic bodies (21, 22) and a magnetic field detection element (3, 12, 13, 14) comprising three GSR elements. For three axial directions that are orthogonal to each other at an origin point that is the center point of measurement, the invention measures, for a first axial direction, a first-axial-direction magnetic field using two elements sandwiching the origin point, measures, for a second axial direction, a second-axial-direction magnetic field through disposing one element at the position of the origin point, and measures, for a third axial direction, a third-axial-direction magnetic field through combining the two elements for the first axial direction and the three soft-magnetic bodies and forming two crank-shaped magnetic circuits having point symmetry.

A magnetic sensor 1 is provided with: a thin film magnet 20 configured with a hard magnetic material and having magnetic anisotropy in an in-plane direction; a sensitive part 30 including a sensitive element 31 configured with a soft magnetic material and disposed to face the thin film magnet 30, the sensitive element 31 having a longitudinal direction in which a magnetic flux generated by the thin film magnet 20 passes through and a short direction, having uniaxial magnetic anisotropy in a direction crossing the longitudinal direction, and sensing a change in a magnetic field; and a control layer 102 disposed on a side of the thin film magnet 20 opposite to a side of the thin film magnet 20 on which the sensitive element 31 is provided, the control layer 102 controlling the magnetic anisotropy of the thin film magnet 20 to be directed in the in-plane direction.

An MI sensor includes: an amorphous wire; an insulator layer formed on an outer peripheral surface of the amorphous wire; and an X-axis coil, a Y-axis coil, and a Z-axis coil which are formed, in a spiral shape, on an outer peripheral surface of the insulator layer. The X-axis coil, the Y-axis coil, and the Z-axis coil are formed of a conductive layer, and the X-axis coil, the Y-axis coil, and the Z-axis coil are arranged in directions orthogonal to each other.

A magnetic sensor, comprising: a substrate having a groove; two conductive magnetic wires for magnetic field detection arranged adjacent and substantially parallel to one another and at least partially recessed in the groove on the substrate, the two conductive magnetic wires electrically coupled at one end; a coil surrounding the two magnetic wires; two electrodes coupled to the two conductive magnetic wires for wire energization; and two electrodes coupled to the coil for coil voltage detection.

Examples of systems and methods for calibrating or operating a magnetic sensor for sensor temperature or operating conditions are provided. The magnetic sensor can comprise a dual magnetometer sensor that comprises a first, low-power-consumption magnetometer (e.g., a magneto-inductive magnetometer) and a second higher-power-consumption magnetometer (e.g., a magneto-resistive magnetometer). The second magnetometer can have a lower unit-to-unit variation in temperature calibration parameters and can be used to temperature-correct readings from the first magnetometer. The magnetic sensor can dynamically switch between usage of the first magnetometer and the second magnetometer in order to provide a dynamic sample rate that can depend on conditions within the sensor or external to the sensor.

A method for non-invasively imaging plasma parameters has been invented. Crossed dipole pairs are used to differentiate changes in the measured complex self- and mutual impedances due to plasma density and magnetic field. Measurements of the complex self-impedance and mutual impedance between pairs of antennas over a wide range of frequencies provide spatial information to create an image of the plasma density and magnetic field. The spectral information is acquired simultaneously using a Gaussian monopulse as the driver signal.