A Train Approach Alarm System Based On DMR Communication Protocol

According to statistics,in recent years,over 17% of the total railway construction accidents are caused by errors in safety protection work.With the increase of operating mileage of high-speed railway in china,the working safety of people and running safety of the train becomes more and more important,and how to improve it has become a major challenge at present.There are many ways to warn train approaching.Because the train speed was getting higher and the train load was getting heavier,thus,the distance of train emergency braking is obviously longer.The exist old warning ways can not meet current needs of train approaching early warning.This paper designs a new train approaching alarm system,which is based on the DMR protocol and dispatching and calling system.The system combines the global positioning system and the china train control system(CTCS)to real-time monitor the position and speed of on-line running trains.The alarm system will send the urgent warning information to the portable radio when the train arriving.Because the system calculate the approaching time of trains and send warning message automatically,human operation mistake is reducing,Using DMR standard,good expansible,convenient deployment.This Paper studies the software architecture and mechanism of the train approaching alarm system,in this paper,a map matching train position method is introduced,such as the tangent track is using method of projection and the same-direction tangent method is used for the circular curve.Further more,this paper also studies the realization of the square root raised cosine filter in modulation part.Finally,this paper makes some experiments such as compatibility experiment and concurrent experiment,the experimental results are in the line with expectations.