Magnetic-interference-free dual-electric compass

The purpose of this research is to improve the reliability of automobile navigation system that utilizes the electric compass for localization. On account of its sensitivity to external interferences of the magnetic field, the electric compass itself is not accurate enough to be used for localization compared with the rate gyroscope. To overcome this shortcoming, in this research, a robust electric compass was designed by using two electric compasses to efficiently cancel out the low-frequency interferences. That is, in this paper, a dual-compass predictive calibration algorithm, which corrects irregular and long-lasting magnetic-field interferences, is newly proposed and implemented. When the external interferences are eliminated from the dual-electric compass, it becomes much more accurate than the gyroscope-based system that suffers from accumulative drift error. The reliability and performance of the designed system were verified through real navigation experiments.