VECTORIAL CALIBRATION OF 3D MAGNETIC-FIELD SENSOR ARRAYS

The vectorial calibration of magnetic field sensor arrays along three axes is presented. In this context, a distinction must be made between the calibration of alignment errors between the 3D sensors and the ca libration of orthogonality errors between the three axes of a 3D senso r. Alignment errors within the sensor array are determined by using a homogeneous vector field generated by a 3D Helmholtz coil arrangement consisting of single octagonal coils. Two sophisticated methods to det ermine errors of orthogonality between the axes of a 3D sensor are des cribed and compared. The first attempt was to calibrate the perpendicu larity of the 3D coil system by means of a laser-interferometer contro lled 90 degrees turn of a solenoid coil and measuring the induced volt age. The second attempt was to use the mechanically fixed perpendicula rity errors of the 3D sensor and the 3D coil system. By rotating the 3 D sensor in the coil system, the perpendicularity errors of coil syste m and sensor are superimposed with changing signs and could therefore be calculated. The measurements are taken across a solenoid coil which can be calibrated by the PTB (Physikalisch-Technische Bundesanstalt-F ederal Standards Laboratory).