Three Axis Fluxgate Magnetometer Array Calibration Using Nonmagnetic Rotation Platform

Three axis fluxgate magnetometer array can be powerful instruments in magnetic mapping and ferromagnetic object localization. The major errors of magnetometer array are caused by sensor triplet deviations (mutual misalignment). A magnetometer array connected by a cross aluminium frame is designed, which contains four three-axis DM-050 fluxgate magnetometers. A convenient array calibration method is presented by rotating a nonmagnetic rotation platform around its axis, and triplet deviations can be estimated. The horizontal deployment of rotation platform is not strictly, and the rotation angle is not strictly required. The generality of computed triplet deviations is tested when the array is deployed with random attitudes. Experimental results show that RMS error of misalignment has been decreased from 802.216 nT to 9.065 nT. In addition, a ferromagnetic object with the size of 15 mm x 75 mm x 55 mm is detected by the calibrated array, and its position is obtained accurately in 3D. It suggests a convenient and effective way for the calibration of three axis fluxgate magnetometer array.