Bias and linearity measurement of three axis fluxgate magnetometers using high precise electromagnetic devices

Bias error and linearity error influence the measurement precision of three axis fluxgate magnetometers. So, it is important to obtain and calibrate these errors. Bias error and linearity error of a German made DM-060 digital magnetometer are measured by precise electromagnetic devices. Firstly, bias of each axis is obtained by an alternating weak electromagnetic standard equipment. A method by comparing mean absolute error before and after calibration is proposed to demonstrate the bias results credibility. Then, the rotating method is proposed to measure bias by a horizontal barrel shield equipment. Lastly, linearity error of each axis is obtained by a low DC electromagnetic field standard system, and linearity coefficients are calculated by linearity fitting. Experimental results show that bias of X, Y and Z axis is -2.9 nT, -1.4 nT and 3.9 nT by the alternating weak electromagnetic standard equipment, respectively. Bias of each axis changes to -5 nT, -2.5 nT and 10.5 nT by the horizontal barrel shield equipment a year later. Linearity error of X axis, Y axis and Z axis is 3.78-e005, 4.51-e005 and 7.92-e005, respectively. These experimental results show that there is a promising application to use high precise electromagnetic devices for measuring and calibrating bias error and linearity error.