| 摘要 |
For localizing positions along roads and railways it is traditional to use a combination of visual observation of one or a row of kilometring markers and the use of a trip counter, but this is connected with a high potential inaccuracy. In accordance with the invention use is made of a detector that will respond to the passage of electromagnetic markers (8, 14, 20) mounted in or underneath the road, such that an automatic determination of a position is achievable either by a tachometric counting of the markers being passed, when these are mounted with a constant mutual spacing, or by the use of self-identifying position markers, combined with the use of an automatic trip counter. Such a marker system is well suited, inter alia, for use in automatic train control systems, as the markers will not interfere with maintenance works in the ballast of the permanent way (18). |
