A magnetic-field measuring apparatus includes a SQUID; and flux-locked loop circuitry including first circuitry that includes an amplifier connected to an output of the SQUID, and second circuitry connected to the first circuitry. The first circuitry is along an inner surface or an outer surface of a shielding material that separates an inside of a magnetically shielded room from an outside of the magnetically shielded room, the magnetically shielded room including the SQUID. The second circuitry is in the outside of the magnetically shielded room.

Disclosed is a method to remove distortion from a navigation system. The navigation system may be used to perform a procedure on a subject. The procedure may be any appropriate procedure. The navigation system may be used to account for the distortive effects of various conductive objects positioned near the subject on which the procedure is performed.

An object of the present invention is to provide a magnetic sensor capable of detecting a magnetic field to be measured through closed loop control even when the magnetic field is weak. A magnetic sensor includes magnetic layers 41 and 42 opposed to each other through a magnetic gap G1, a magneto-sensitive element R1 disposed on a magnetic path formed by the magnetic gap G1, and a compensation coil 60 generating canceling magnetic flux ϕ4 to cancel magnetic flux ϕ2 applied to the magneto-sensitive element R1. According to the present invention, magnetic flux ϕ2 flowing in the magnetic layers 41 and 42 each functioning as a yoke is applied to the magneto-sensitive element R1, so that even when a magnetic field to be measured is weak, it can be detected. In addition, closed loop control can be performed due to the presence of the compensation coil 60 that cancels magnetic flux ϕ2.

An object of the present invention is to provide a magnetic sensor capable of detecting a magnetic field to be measured through closed loop control even when the magnetic field is weak. A magnetic sensor includes magnetic layers 41 and 42 opposed to each other through a magnetic gap G1, a magneto-sensitive element R1 disposed on a magnetic path formed by the magnetic gap G1, and a compensation coil 60 generating canceling magnetic flux ϕ4 to cancel magnetic flux ϕ2 applied to the magneto-sensitive element R1. According to the present invention, magnetic flux ϕ2 flowing in the magnetic layers 41 and 42 each functioning as a yoke is applied to the magneto-sensitive element R1, so that even when a magnetic field to be measured is weak, it can be detected. In addition, closed loop control can be performed due to the presence of the compensation coil 60 that cancels magnetic flux ϕ2.

A magnetic field measurement cable (10) of the present disclosure includes an electric cable (1) provided at an axial part, and an outer circumferential cable (2) provided on the outer side of the electric cable (1) and helically formed by a plurality of steel wires helically wound and a magnetic field measurement optical cable (3) having an optical fiber cable (3a).

A magnetic field measurement cable (10) of the present disclosure includes an electric cable (1) provided at an axial part, and an outer circumferential cable (2) provided on the outer side of the electric cable (1) and helically formed by a plurality of steel wires helically wound and a magnetic field measurement optical cable (3) having an optical fiber cable (3a).

Magnetic field sensors and sensing methods are provided. A magnetic sensor module is configured to measure a magnetic field whose magnitude oscillates between a first extrema and a second extrema. The magnetic sensor module includes a magnetic sensor configured to generate measurement values in response to sensing the magnetic field, and a sensor circuit. The sensor circuit is configured to generate a measurement signal based on the measurement values, adjust an offset of the measurement signal according to an offset update algorithm and a first characteristic of the measurement signal, generate a pulsed output signal having pulses that are generated based on the adjusted measurement signal crossing the switching threshold, and selectively enable and disable the offset update algorithm based on a second characteristic of the measurement signal.

Magnetic field sensors and sensing methods are provided. A magnetic sensor module is configured to measure a magnetic field whose magnitude oscillates between a first extrema and a second extrema. The magnetic sensor module includes a magnetic sensor configured to generate measurement values in response to sensing the magnetic field, and a sensor circuit. The sensor circuit is configured to generate a measurement signal based on the measurement values, adjust an offset of the measurement signal according to an offset update algorithm and a first characteristic of the measurement signal, generate a pulsed output signal having pulses that are generated based on the adjusted measurement signal crossing the switching threshold, and selectively enable and disable the offset update algorithm based on a second characteristic of the measurement signal.

A magnetic field sensor for detecting a direction of a magnetic field comprises an xMR sensor designed to produce an xMR sine signal and an xMR cosine signal based on the magnetic field, and an AMR sensor designed to produce an AMR sine signal and/or an AMR cosine signal based on the magnetic field. A processing circuit is designed to determine the direction of the magnetic field using the xMR sine signal, the xMR cosine signal, a first phase difference between the xMR sine signal and the AMR sine signal or the AMR cosine signal, and a second phase difference between the xMR cosine signal and the AMR sine signal or the AMR cosine signal.

A magnetic field sensor for detecting a direction of a magnetic field comprises an xMR sensor designed to produce an xMR sine signal and an xMR cosine signal based on the magnetic field, and an AMR sensor designed to produce an AMR sine signal and/or an AMR cosine signal based on the magnetic field. A processing circuit is designed to determine the direction of the magnetic field using the xMR sine signal, the xMR cosine signal, a first phase difference between the xMR sine signal and the AMR sine signal or the AMR cosine signal, and a second phase difference between the xMR cosine signal and the AMR sine signal or the AMR cosine signal.