Development and error compensation of a low-cost digital compass for MUAV applications

In this paper a reliable, low-power and low-cost digital compass which can provide heading information to micro-unmanned air vehicle (MUAV) is designed with 3-axis sensors and a method of compensating errors is developed. The method of error compensation proposed utilizes the fact that the attitudes of MUAV are classified as level flight, turning left and turning right and the ellipse fitting method based on three attitudes is applied to compensate errors. In order to avoid the failure of compensation algorithm, the method of data acquisition for the magneto-resistive sensor is proposed. Experiment results show the digital compass designed can update the heading information at the speed of 50Hz and the heading measurement error is less than 3°, and so it may be acceptable for MUAV applications.