The Methods of Accurate Measurement of Tilt Azimuth within Small Angles of Tilt

Abstract

This article focusses on the determination of the tilt azimuth within the small angles of tilt using accelerometer. Azimuth is usually acquired using magnetometers and is then called the magnetic azimuth. In practice, magnetometers are commonly accompanied by other inertial sensors or filtering. The azimuth can be relatively easily acquired using a single magnetometer, which has to be properly calibrated against the magnetic materials in its surroundings. For further improvement in accuracy of measurement, a sensor fusion or filtering is necessary. The advantages and drawbacks of using magnetometer and filtering are discussed. In contrast to these more complex techniques, a different configuration of measurement is used further in the article. The main focus is to present a low-cost and easy-to-integrate method of measurement. It consists of the definition of the accelerometer position, which is rotated by 45°. In this configuration, the accelerometer alone can be used to determine the azimuth of the tilt and the tilt itself. That is given by the better distribution of gravitational force among accelerometer axes and their sensitivity. This is prooved by mathematically derived equations. In the final results, the measurement with the rotated accelerometer is shown, and the improvement in accuracy and statistics is determined.