Based on the model of safe following distance , the design blue print of system is presented in the text . using the multiple impulses horae rotate speed sensor to measure the vehicle speed and nanometer radar to measure the distance of own vehicle to frontal vehicle , and analyzing and judging collected information by at89c51 which is the control centre of the system 本文在安全跟车模型的基础上，提出了系统方案：采用霍尔多脉冲转速传感器测量汽车的速度，毫米波雷达测量两车的距离和相对速度，利用at89c51作为信息采集单元的控制中心，对各种信息进行分析判断，当行车距离小于报警距离时启动相关的报警单元。
