倒车测距，1、分析了超声波传感器的工作原理、工作特性和探测盲区；

2、对倒车测距仪要求对前、左、右两侧30度夹角范围内进行测量；

3、距离范围要求20m以内，小于1.5米开始报警，小于1米进一步报警提醒；

4、完成倒车测距系统电路设计，绘制原理框图和电路图，编制软件程序。

-Ranging reverse, 1, an analysis of the working principle of ultrasonic sensors, the working characteristics and blind spot detection　2, on the reverse range finder called for the former, left and right angle of 30 degrees on both sides of the fr a mework of measurement　3, distance requirements less than 20m, less than 1.5 meters began to report to the police, less than 1 m further alarm to remind　4, the completion of Ranging System reversing circuit design, drawing and circuit diagram, the preparation software program.