Performance Monitoring and Analysis of Down-Link Signal in Balise-based Train Positioning System.

To monitor and analyze of the down-link signal transmission performance of the balise-based train positioning system (BTPS), a new performance monitoring and analysis parameter is proposed. This paper builds a transmission model of downlink signal in BTPS, and describes the shortcomings of the existing performance monitoring and analysis methods. By analyzing the equivalent circuit schematic of the on-board antenna and the balise antenna, the input impedance is proposed as an important parameter for evaluating the down-link signal transmission performance. 6 statistical features are extracted from the main lobe envelope curve of the real part of the complex input impedance, the transmission performance of down-link signal in BTPS at different train operating condition are analyzed. The simulation results demonstrate the effectiveness of the input impedance for analyzing the transmission performance of down-link signal in BTPS.