method of calibration for sensors of magnetic field devices, system, apparatus and computer product corresponding

摘要

Calibrated sensing signal components ( X cal , Y ca / , Z cal ) represented in a three-dimensional coordinate system (X, Y, Z) by a spherical graph (S) centered at the origin (O) the three-dimensional coordinate system (X, Y, Z) are generated from uncalibrated signal components ( X unc , Y unc , Z unc ) from a magnetic field sensing device, e.g. a magnetometer (M), represented in the three-dimensional coordinate system (X, Y, Z) by an ellipsoidal graph (E) having a center (CE) offset with respect to the origin (O). Kalman filter processing (104) is applied to the sensing signal components yielding a set of parameters (X(8:0)) fitting the ellipsoidal graph (E) by prediction and correction based on prediction. The set of parameters (X(8:0)) fitting the ellipsoidal graph (E) as obtained from Kalman filter processing (104) are processed by: - a) translating the center (CE) of the ellipsoidal graph (E) towards the origin (O) of the three-dimensional coordinate system (X, Y, Z), - b) rotating the ellipsoidal graph (E) to align the axes thereof with the sensing device (M) axes, - c) scaling the ellipsoidal graph (E) to a sphere (S), and - d) back-rotating the sphere (S) resulting from scaling to the orientation of the ellipsoidal graph (E) before rotation.