| Balise system is an important part of train operation control system as an infrastructure to ensure safety and efficiency of train transportation.The uplink of the Balise is an important channel for the communication of the balise system,which is easily affected by the external electromagnetic interference and affects the driving safety.It is of great significance to study the influence of the electromagnetic pulse on the uplink of the answer device.Based on the actual scientific research project of the Electromagnetic Environment Effect Research Institute of Shijiazhuang TieDao University,this paper studies the modeling of the uplink of balise,analyzes the influence of the electromagnetic pulse on the uplink of the answer device,and discusses the electromagnetic field after the BTM antenna is installed with the shield board.Pulse shielding effectiveness,specific work as follows:(1)Modeling,simulation and verification of balise uplinkFirstly,according to the Standard Specification for the balise,establishment of balise uplink antenna model for coupling communication,balise antenna and BTM antenna,and tuned so that the model meets the balise communication standard,from the balise signal transmission,balise uplink field consistency to verify the feasibility of the model.In order to fit the reality,a model of rail and car body is established in this paper,which provides a simulation model for the study of the influence of electromagnetic pulse on the uplink of the answer device.(2)The influence of electromagnetic pulse on the uplink of answering machineBy analyzing the characteristics of the time and frequency domain of the typical electromagnetic pulse,the energy distribution of the electromagnetic pulse with different time frequency characteristics in different frequency bands is obtained.The interference current of electromagnetic pulse on the BTM antenna port coupling is simulated and calculated,and the influence of electromagnetic pulse on the uplink of the responder is analyzed based on the time frequency characteristics and the energy ratio of the pulse.The coupling rules of the electromagnetic pulse corresponding to the uplink of the responder with different rising angles,different incident angles and different polarization angles are studied,which provides a theoretical basis for the electromagnetic protection of the uplink of the Balise.(3)Shielding effectiveness analysis of shielded plate to BTM antennaAccording to the basic method of electromagnetic protection,the shielding effectiveness of the shielded plate to the BTM antenna is studied.The material,horizontal distance and height of shield plate are simulated and analyzed,which ensures that the shielding performance of metal material will not affect the performance of BTM antenna.The shielding effectiveness of shielding panels is calculated.The results show that metal shield has better shielding effectiveness for electromagnetic pulse,and the shielding effectiveness of copper material is better than that of iron. |
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