Research of SDS-TWR ranging based on collision avoidance of anti-collision warning system in urban rail train

Anti-collision warning system is very important for urban rail train in ATP failure situation. The ranging method based on SDS-TWR principle can give the good ranging precision and long distance. However, in the case of multi-train, especially near the train node, the anti-collision warning system cannot work normally when the signal collision channel is busy. Combining the RFID label information, collision avoidance mode can promote fairness as all stations have equal probability of gaining access to the media. The method of SDS-TWR is used to model the wireless location of urban rail trains under high-speed moving conditions, and the actual measurement results are presented. The method proposed in this paper can effectively realize the distance detection of collision warning and improve the usability of train crash warning equipment in complicated environment.