Sensors – Data – Algorithms

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The use of trackside components such as axle counters in the positioning of rail vehicles results in relatively high fixed costs for lines with low traffic densitiy. By moving the positioning function including the necessary technology to the vehicle, these costs can be lowered on regional lines, making operations more economical. This is why DLR develops vehicle-based GNSS positioning systems according to customer requirements. DLR also focuses on other applications of vehicle-based positioning systems, such as the updating of train movements to permit forecasting of future train routes, and georeferenced status information for both infrastructure and vehicles. Systems of this kind, which provide combined condition and positioning information, can be used for purposes such as improved maintenance planning and logistics, or travel information.

A framework developed by DLR synchronously logs the multiple sensor data. This permits playing back these data for a realistic simulation, to test prototype sensor-based algorithms for the positioning and status logging of rail vehicles or the track system.

DLR moreover develops the algorithms required for an online fusion of the positioning sensor data. They serve to combine GNSS and vehicle sensor data and to synchronise them with a digital route map; this is called „map matching". The algorithms also take into account rail-specific boundary conditions. Thanks to its modular system architecture, the positioning system can easily be tailored to customer requirements and the intended applications.

One research focus in the development of positioning systems is the derivation of conclusions about the reliability of positioning results in terms of their integrity. This is the key requirement for the integration of an innovative positioning system into safety-critical applications.

The road-rail vehicle RailDriVE®, built as a mobile testing laboratory, is equipped with positioning, communications and computing technology and can thus be used for the partly automated generation of digital route maps, or as a reference for the validation of sensors and systems of external partners or clients. It shares data with the railway simulation and testing laboratory RailSiTe® and the railway simulation environment for train drivers and operators RailSET®, thus permitting a consistent use of geodata in the three laboratories. Since digital maps are essential for the trackside-based positioning of rail vehicles, DLR is also actively collaborating in the standardisation of exchange formats for map data and the development of a concept for the life cycle management of digital route maps.

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