Development of rear sonar using exhaust sound of automobile

本研究的目的是利用汽车消声器发出的汽车尾气声实现汽车后声纳对汽车后方障碍物(或目标)的探测。(1)分析了基于可听声位相干扰的距离估计方法的基本性质和潜力。(2)提出了几种减小扬声器、目标和传声器几何位置误差以及观测噪声和测量系统影响误差的方法。此外，(3)提出了一种距离测量方法，用于测量小于最小可测距离的距离。

The purpose of this study is to realize a rear-sonar of automobile for detecting obstacles(or targets) behind the automobile, using the exhaust sound of the automobile emitted from the automobile muffler. (1) We considered the fundamental properties and potentials of the distance estimation method based on the phase interference of audible sound. (2) We developed several methods, so as to reduce the error due to geometrical positions of the loudspeaker, target and microphone and the error due to the effect of the observation noise and measurement system. Furthermore, (3) we proposed a distance measurement method to measure the distance shorter than the minimum measurable distance.