Modelling multiple reflection paths in ultrasonic sensing

Multiple reflection echoes are considered to be a source of errors in range readings because the simple model relating distance of flight to range is inaccurate. If the geometric path of the echo is known then it is possible to calculate the position of the reflecting object. In this paper, we developed a model of multiple reflections from the virtual source model. This model was validated by experiments with a mobile robot for the common situation of multiple reflection from a corner. By combining this multiple reflection model with the are model of ultrasonic sensing, we developed a virtual beam model which determines the path of a beam after multiple reflections. This model was validated experimentally by comparing its results to measurements made by a robot as it approached a corner. The models developed in this work are a first step toward solving the problems caused by multiple reflection paths for ultrasonic echoes