The current position detection system for tilting-type cars with control function is based on the ATS signal detected. However, this can take time as the latest position of the wayside coil needs to be constantly input. Moreover, if a speed detector error occurs due to a slide or wheel slip, or if the wheel diameter setting is different from the actual wheel diameter, it may become impossible to check the wayside coil position. This is a leading factor in normal tilting control blockage.
      To resolve these problems, a system using the Global Positioning System (GPS) was developed as an autonomous running position detection system independent of ground facilities. The arrangement combines the following three systems (Table 1): (1) GPS positioning data, (2) linear information checking, and (3) a system using speed-accumulative distance. Using this, the running position of a vehicle in any running state (including those in tunnels) can be determined. A running test using these three combined systems (Fig. 1) showed greater precision than the current system, with a fixed point detection error margin of 4 m or less (Fig. 2). The fixed point detection error margin using only GPS-measured positions varied widely, with a maximum value of about 34 m.