Train position detecting system using radio millimeter-waves

Abstract

This paper describes how the Maglev on the Yamanashi Test Line is driven by Linear Synchronous Motor (LSM). Train control needs a precise position of the train in order to achieve stable and efficient operation of the LSM drive. Moreover, the information of the train position is important from the viewpoint of safety, because it is used to check a train speed for safety brake control that assures the last method. In the Yamanashi Maglev Test Line, a train position is detected by the inductive radio system. The inductive radio system is reliable and accurate. On the other hand, the cost of construction and maintenance of the inductive radio system is expensive, because the cross-inductive cable has to be laid along the guideway accurately and the Local Position Detectors have to be installed about every 2km. Thus, the train position detecting system has been developed without inductive wire in order to reduce construction and maintenance cost. It detects the train position by a combination of several methods, such as an Electromotive Force (EMF) observer, a tachometer of the wheel, a counter of ground coils for levitation and guidance, and radio millimeter-waves. Out of those detecting methods, the train position detecting system using radio millimeter-waves is presented in this paper.