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Location detection by permanent evaluation of the light train's wheel signals

In Europe, the controlling of the passenger information system inside a vehicle, busses and (light) trains, is generally done by an On Board Computer (OBC). This OBC can be a Man Machine Interface (MMI) also. In this case the OBC is placed near to the driver.

Init GmbH, a subcontractor of LLE®-MARK IV Industries GmbH, had equipped Karlsruhe’s light trains independently from the ELBA-project with their On Board Computer system called "copilot", which is a family of vehicle logic units (VLU) and mobile data terminals (MDT), long before our project started. “Copilot” has been developed according to a modular hardware and software concept. More information regarding the init-OBC “copilot” can be found at

The first „copilot“ generations were developed and produced in accordance with the strict and comprehensive standards of the German VDV (Verband Deutscher Verkehrsunternehmen = German Federation of Public Transit Operators; equivalent to APTA or CUTA) and extended with various highly sophisticated functions and features.

“Copilot” is an intelligent unit acting as the interface to both the vehicle electronics and the on-board radio communication system. It is also the man-machine interface to the vehicle operator. The unit is equipped with a display and a very convenient keyboard.

Odometer Interface
For calculation of the current position of the vehicle, the „copilot“ has an odometer interface. When the vehicle is in motion, the odometer delivers signals, which are counted by the “copilot”. This interface requires an existing output signal from the odometer sensor of the vehicle. This has to be a rectangle signal with the following characteristics:

The complete route information data, all stops and the distance between these stops in meters, are stored inside the OBC. The OBC is analysing external odometer signals (4 times 24V-signals per meter). The internal Meter-Counter is synchronized at the beginning of a route and whenever the light train leaves a stop. Therefore the OBC knows the position inside the route or between two stops exactly at any time.

Both systems, OBC and Infotainment System, are connected by the vehicle data bus, which is called IBIS (Integrated Board Information System). Beside the standard IBIS-telegrams concerning route information data (line-number, destination-number, route-number, next stop-number, all stops of a route, time, date, a. o.) in the case of E-LBA new IBIS-telegrams were defined and realized. These new LBA-telegrams include distance- and status- (e.g. door open or closed) information between two stops.

This method for the determination of the train's current position is used to determine when a certain advertisement is to be shown in the light train's infotainment system. As described before, every advertisement should be displayed immediately before the train approaches the station, which is closest to the related shop. To reach this, the evaluation of the light train's wheel signals is the perfect method to know exactly the relative position of the train.

Reported by

LLE Mark IV Industries GmbH
Stockfeldstr. 1
76437 Rastatt
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