当信号系统失效情况下，调度人员无法获悉列车位置，现有后备模式和电话闭塞法指挥行车存在效率低下的问题，且具有一定的安全隐患。本系统通过列车速度传感器、加速度传感器提供速度信息，持续计算列车位移，并通过PIS(Passenger Information System, 旅客信息系统)网络通道传送给车载定位服务器，车载定位服务器再结合信号系统故障时刻的位置信息，计算出列车的最新位置信息，实现列车实时定位。系统在合肥轨道1号线进行验证，结果表明，该系统在全线及个别列车信号系统故障情况下，均能实现列车实时定位，站间平均误差＜1m，全线定位误差率＜1‰，全线单程累计误差距离＜20m。

When the signal system fails, the dispatcher cannot know the position of the train. The existing backup mode and the telephone blocking method have the problem of low efficiency and certain safety hazards.The system provides speed information through the train speed sensor and acceleration sensor, continuously calculates the train displacement, and transmits it to the on-board positioning server through the PIS(Passenger Information System) network channel. Real-time train positioning. The system was verified on Hefei Railway Line 1. The results show that the system can achieve real-time train positioning under the condition of signal system failure of the entire line and individual trains. The average error between stations is less than 1m, the positioning error rate of the whole line is less than 1‰, and the one-way cumulative error distance of the whole line is less than 20m.