RUNE (Railway User Navigation Equipment): Architecture & Tests

Abstract

Due to European on-going developments (EGNOS, GALILEO), satellitenavigation is now an interesting innovation for all fields of transport.One of them is the railway domain, which could considerably profit fromthe implementation of autonomous on-board positioning systems. Forrailway transportation, satellite navigation offers new opportunities toincrease accuracy of positioning and to implement safety standardseverywhere, from high speed trains to local and regional railway lines,enabling a cost-effective modernization and increase of efficiency.Train control poses high demands on positioning with respect toavailability, reliability and integrity. Meeting these requirements witha GNSS-based navigation system is the objective of several projects andstill needs to be proved.RUNE is a project developed for the European Space Agency by AlcatelAlenia Space Italia (Laben Directorate), leading a team comprised of VIARail Canada Inc. (VIA), Ansaldo Segnalamento Ferroviario (ASF), andINTECS HRT. In this project, the European Geostationary Overlay Service(EGNOS) has been used as part of an integrated solution to improve thetrain driver's situational awareness. RUNE integrates positioningsensors with signalling and speed constraint information from a controlcentre. This can improve safety as a result of a better situationalawareness and can also speed up the deployment of drivers on new routes.The primary objective is to demonstrate the improvement of the trainself-capability in determining its own position and velocity withlimited or no support from the track side, still complying with EuropeanRailway Train Management System (ERTMS) requirements. The achievement ofsuch objective could lead to the reduction of physical balisesdistributed along the track line and needed to reset the train odometererror. Substituting physical balises with GNSS-based virtual balises canlead to reduction of infrastructure costs.The RUNE project development has gone through a HW-In-the-Looplaboratory set-up up to field-testing. Field tests of the equipment wereperformed in Italy on the Torino-Chivasso line in April 2005, on board aTrenitalia ALE-601 experimental train. The unit included an LI GPS/EGNOSreceiver, Profibus and CTODL interfaces to the train odometer and BTM,an IMU sensor for dead-reckoning positioning, virtual balise andvelocity profile databases. This paper presents an overview of RUNE andprovides results of the analysis performed on the data collected fromthe experimental train test campaign. Although testing duration waslimited, collecting and analysing real data is important for buildingexpertise in system behaviour and for algorithms evaluation and tuning.Those initial results show achieved performance in the real environmentand the capability of the system to provide In-Cab Signalling andVirtual Balise functionalities. It is recognized that only throughextensive field testing and validation of the system architecture andalgorithms it will be possible to build a robust certifiable GNSS-basedtrain navigation system.