Correction Method of Estimated Distance

Abstract—In many engineering fields, distance to target is very important and fundamental information. Acoustical sig-nal often plays an essential role in measurement of distance. Though there are distance measurement methods using a time delay between transmitted and reflected waves, it is difficult to measure short distance because the transmitted wave suppresses the reflected waves for short distance. Recently, in a research field of microwave, a method for measuring the short distance has been proposed using interference (i.e., standing wave) of transmitted and reflected waves. We applied the fundamental principle of this method to the estimation of short distance using audible sound as a transmitted wave. Until now, this method supposed that microphone was set at the straight line between a sound source and a target. However, we can not estimate exactly the distance between the microphone and target when th