A fluxgate magnetometer for navigation and sensing: Noise character and digital filtering

Vector fluxgate magnetometers are an important category of geomagnetic sensors in aircrafts´ navigation and sensing applications for compact form factor and low power consumption relative to their quantum counterparts. In this work, a navigation grade vector fluxgate magnetometer is developed with a traditional transformer based square-wave exciter. It is shown, by both experimental results and theoretical analysis, that the excitation distortion due to the capacitance and resistance internal to the transformer is a main interference source limiting the magnetometer´s noise performance. For improvement, a digital filter is introduced in to process the noise. And still, all the calibrations are also managed by digital processing. The results show that: (1) the noise of the proposed magnetometer is 0.1nT(RMS) at 0.1-1Hz, and 0.347nT(RMS) at 0.1-20Hz; (2) the analogy circuit of the proposed fluxgate magnetometer has a power consumption of only 0.3w, and the total power consumption is 1.1W.