MAGNETIC SENSING SYSTEM, DETECTION DEVICE, AND MAGNETIC INTERFERENCE OFFSET METHOD

摘要

This magnetic sensing system 10 comprises a sensing device 11 for generating an electrical signal according to the strength of a magnetic field that changes in association with the action of an external force and a detection device 12 for using the change in the magnetic field according to the electrical signal from the sensing device 11 to detect a physical quantity associated with the action of the external force. The sensing device 11 comprises magnetic field generation means 15, 18 that generate, from a region that is displaced through the action of the external force, a desired measurement magnetic field having differing strengths and a magnetic field measurement means 19 for measuring the strength of a surrounding magnetic field including the measurement magnetic field. The detection device 12 uses a relational expression stored beforehand to specify, on the basis of fluctuations over time in the measurement magnetic field having differing strengths, a magnetic interference amount corresponding to the strength of an interfering magnetic field generated separately from the measurement magnetic field and determines the physical quantity by removing the influence of the magnetic interference amount.