Direction of echo arrival estimation by indirect determination of the phase shift

Abstract

The problem of incident angle determination for an ultrasonic signal is the main concern of this paper. The problem is considered for a 2-D case when the azimuth angle of echo arrival direction has to be established. Information of that direction is essential for the improvement of data reliability obtained from an ultrasonic range finder. It provides an opportunity for many applications, not only in robotics for obstacle detection, but also in many other areas, e.g., gesture recognition. To determine an incident angle, an approach based on indirect determination of the echo phase shift is presented and discussed. An error analysis is presented and it is shown how a measurement error of signal arrival affects an application of that method. Some preliminary results are presented at the end.