A novel method of train positioning based on visible light communication

Train position information is the key factor to ensure the safe and efficient operation of trains for CBTC (Communications Based Train Control) systems. Aiming at the unique characteristics of tunnel environment and train operation for urban rail transit, a train positioning method using VLC(visible light communication)and RSSI (Received Signal Strength Indication) has been proposed, and the visible light communication train positioning system is established. Firstly, based on the classical illumination model of Lambert, a train positioning model with LED lamps for CBTC systems has been established. Secondly, The visible light communication positioning system is designed. Thirdly, the linear distance between the LED lamps and the train on the tunnel wall is calculated by using the RSSI value, and the train positioning results are fitted by using the trilateral positioning principle and the least square method. Finally, according to the real line data and equipment parameters from Chengdu Metro Line 1, the feasibility and effectiveness of the proposed method has been verified. The simulation results show that the maximum positioning error is 9. 4cm, and the average positioning error is less than 10cm,all of these meet the CBTC train positioning requirements. VLC-based positioning can be used as a new choice of train positioning method.