Design of miniature electronic compass based on GMR sensor

SHI Shao-hua1， QIAN Zheng-hong1， BAI Ru1， GONG Tian-ping2， SUN Yu-cheng1
（1. Center for Integrated Spintronic Devices（CISD），Hangzhou Dianzi University， Hangzhou 310018， China；
2. SpinIC Co. Ltd.，Yichang 443003， China）

Abstract： Aiming at miniaturizing 2-axis electronic compass while maintaining its accuracy, a miniature 2-axis electronic compass based on giant magnetoresistance (GMR) was investigated and realized by optimizing the hardware and arithmetic. In hardware，the novel GMR was chosen to measure magnetic field，and a Δ-ΣA/D converter which is already incorporated into the MCU（C8051F350）was selected to condition the output of GMR sensors. The designed compass is with a compact size，and can be calibrated to eliminate magnetic interference making it suitable for embedded applications. The accuracy of the electronic compass was measured to be ±2° without magnetic interference. Even with the presence of magnetic interference，a relatively good accuracy is still achievable if a proper calibration is done. The results indicate that this electronic compass can be applied in many engineering applications.
Key words： giant magnetoresistance（GMR） sensors；two-axis compass；anti-interferences