倒车雷达只需要在汽车倒车时工作，为驾驶员提供汽车后方的信息。由于倒车时汽车的行驶速度较慢，和声速相比可以认为汽车是静止的，因此在系统中 可以忽略多普勒效应的影响

代码说明：

倒车雷达只需要在汽车倒车时工作，为驾驶员提供汽车后方的信息。由于倒车时汽车的行驶速度较慢，和声速相比可以认为汽车是静止的，因此在系统中 可以忽略多普勒效应的影响。在许多测距方法中，脉冲测距法只需要测量超声波在测量点与目标间的往返时间，实现简单，因此本系统采用了这种方法。-Reversing radar only need to work in the car when reversing, the rear car for the driver to provide information. As the reversing of vehicles traveling at slower speeds, and speed of sound can be compared to consider car is stationary, and therefore in the system can ignore the impact of the Doppler effect. Ranging in many methods, ranging pulse ultrasonic method only measured in the measurement points and the round-trip time between the target and achieve a simple, this system uses this approach.