Precise vector-2D magnetic field sensor system for electronic compass

Abstract

An high sensitivity vector-2D magnetic sensor system for low magnetic field measurements has been realized and tested. The system, realized in PCB technology, consists of a double axis fluxgate magnetic sensor with its front-end electronic circuitry based on second-harmonic detection. The amorphous magnetic materials Vitrovac 6025X (25 /spl mu/m thick) and Vitrovac 6025Z (20 /spl mu/m thick) were used as a ferromagnetic core for the sensor. Applying a sinusoidal excitation current of 450 mA peak at 10 kHz with the Vitrovac 6025Z, the magnetic sensitivity was about 1.25 mV//spl mu/T, suitable for detecting the Earth's magnetic field (/spl plusmn/60 /spl mu/T), while the linearity error is 1.5% full scale. Using the thicker Vitrovac 6025X, a maximum sensitivity of about 1.68 mV//spl mu/T and a linearity error of about 1.55% full scale in the range of /spl plusmn/60 /spl mu/T were obtained with a larger sinusoidal excitation current of 600 mA peak at 10 kHz. The 2D vector sensor system presented is characterized by a very simple process fabrication due to the use of commercially available very thin ferromagnetic material.