Digital Detection and feedback Fluxgate Magnetometer

A new full Earth's field dynamic feedback fluxgate magnetometer is described. It is based entirely on digital signal processing and digital feedback control, thereby replacing the classical second harmonic tuned analogue electronics by processor algorithms. Discrete mathematical cross-correlation routines and substantial oversampling reduce the noise to 71 pT root-mean-square in a 0.25 - 10 Hz bandwidth for a full Earth's field range instrument.