Compact North Finding System

Abstract

The knowledge of orientation of an object with respect to earth-fixed reference coordinate system is crucial in many applications. For instance, in oil mining it is very crucial to accurately know the orientation of the drilling equipment under the earth surface to drill through desired path. In this context we propose a compact inertial sensor system that estimates the instantaneous orientation of the system using accelerometer and gyroscope-derived tilt and azimuth angles. To keep the system size small, we use two-axis accelerometer and one-axis gyroscope. In addition, to avoid high sensor cost, the sensor biases are removed using indexing method. The proposed system estimates the orientation of the compact system in almost all of the orientations and additionally it also provides the measurement accuracy and integrity values that help in ascertaining the validity of the orientation estimate.