Reduction of magnetic noise limits of orthogonal fluxgate sensor

We have further lowered the white noise of an orthogonal fluxgate to about 0.3 pT/√Hz @ 8 Hz. So far, this is lowest reported for a magnetometer. The reduction was achieved by introducing JFET input stage, embedded directly sensor head, allowing high common-mode rejection and negligible loading resonant circuit. origin investigated correlation measurements we concluded that, at least in region, observe magnetic sensor, with 0.1 contribution electronics. were finally able obtain floor below 1 Hz also feedback-compensated closed-loop. Closed-loop operation allows higher magnetometer stability Earth’s field without deteriorating its performance.