CROSSFIELD EFFECT IN COMMERCIAL FLUXGATE AND AMR SENSORS

Pavel Ripka – Michal Janošek – Mattia Butta – William S. Billingsley – Eva M. Wakefield

   Crossfield effect often seriously limits the accuracy of magnetic sensors. However, this effect is only rarely discussed by sensor manufacturers and users. In the case of bulk fluxgates, crossfield error in the Earth’s field can be suppressed by proper design below 3 nT p-p for the race-track and rod fluxgates and also for carefully designed ring-core sensors. Crossfield for miniature fluxgate can be significantly higher mainly due to imperfections in the geometry– for PCB fluxgate we measured 60 nT error. In case of AMR crossfield sensitivity is inherent. Typical high-sensitive sensor has 1000 nT p-p error in the Earth’s field. Feedback compensation of the measured field can effectively suppress this error. If feedback compensation is not possible, we suggest new methods for effective compensation of the crossfield sensitivity such as advanced processing of the flipped sensor output.

Keywords: fluxgate, AMR, crossfield

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