Research On Performance Of Balise Equipment Under Condition Of High-Speed

With the great-leap-forward development of China’s railway construction, the operation speed and the safety of railway get more and more attention, therefore the railway department set up the train automatic control system CTCS which corresponds to China’s national conditions. And as the key equipment in CTCS, the balise supports the normal operation of the train. So the research of balise system is of great value, but the domestic literature on the balise is very few. This paper’s topic selection is based on the above problems. Thesis studies the performance of the balise under condition of high speed from the theory, the simulation and the measured for railway construction service.First, this thesis gives a deep research to the balise and the Balise Transmission Module(BTM) about the working principle, transport interface, function and the message format. Because the communication between the balise and the BTM is an application of high frequency RFID, so the analysis of the RFID theory must be done.The key point of the research on the communication between the balise and BTM is air interface, and it needs antenna theory and coupling between the antenna theory as a foundation. This thesis abstracts out the thin rectangular antenna model, and deduces the calculation formula of near field of magnetic field and coupling calculation formula based on actual balise. Plus with rectangular slices antenna theory and impedance matching theory, a balise antenna whose resonance frequency is4.23MHz and-lOdB impedance bandwidth is1MHz is simulated out. Based on the simulation, the degree of coupling between balise antenna and BTM antenna is got, as well as the greatest function of the distance between two antennas, and they are confirmed by the test data and the theoretical calculation.The high speed capability of balise is the data transmission characteristics between balise and BTM in high speed. So, this thesis analyzes the four factors which influence its high-speed capability, those are Doppler frequency shift, antenna resonant point migration, the dynamic response range and noise interference, Quantitative analysis of those four factor have also been done based on it. The conclusion is that those factors are accord with the standard of balise.Finally, this thesis analyzes the noise influence. The FSK modulation, demodulation and the noise of the channel model is studied. Then an evaluation of the noise interference in FSK channel model has been done base on the test on Beijing to Tianjin intercity high-speed rail. The noise is divided into two classes:the same-phase regional noise from orbit current, electromagnetic stray noise; the split-phase regional noise from inrush current. The same-phase regional noise is very small and will not influence the data transmission, but the split-phase regional noise is different. Author extracts the split-phase regional noise from the measured data, and simulated in FSK channel model. The conclusion is that the split-phase region is the area the balise most prone to "throw away". Thus this thesis put forward two solutions:1) let the first balise100-200meters further away from the split-phase region;2) the second balise must contain the check message.