Measurement Methods for Train Localization with Onboard Sensors

Real-time train localization with onboard mounted sensors is a basis for future railway applications. In contrast to infrastructure based train localization with way-side sensors, the onboard train localization uses only train-side sensors and a digital map of the railway tracks. Therefore, the trains are equipped with sensors, e.g. near the train-front and near the train-end. The train-front location and the train-end location are determined on the tracks in track coordinates with absolute train localization methods. A distance on tracks between two locations is determined with relative localization methods. This distance on the tracks can be used to monitor the train length and also to observe the distance between trains. This paper contains an overview of different measurement methods for speed measurement, absolute train localization and relative train localization based on GNSS (Global Navigation Satellite System), IMU (Inertial Measurement Unit), magnetometers and RF (radio frequency) ranging.