At present, the advanced automatic train control system is widely used in the subway signal system. ATP protection equipment is installed in all operating trains to protect the train, so as to ensure that the train keeps a distance from the front vehicle and avoid collision. However, how to ensure the safe operation of trains running on the subway line when ATP is abnormal, or there is a faulty train, or there is an engineering vehicle on the line, or there are obstacles on the line track, that is, detect the distance between the front and rear trains, calculate the possibility of collision, detect whether there are obstacles on the track that pose a danger to the train operation, and remind the driver in real time according to the situation, Driver Tian's anti-collision skill is that a PI is in the heart of the 10th day, and a son needs to install our obstacle detection radar on the "ATP outer layer" to form the active anti-collision function of the train.