WIT Press

A framework for certification of train location determination system based on GNSS for ERTMS/ETCS


Free (open access)


Volume 2 (2018), Issue 3



Page Range

284 - 297

Paper DOI



WIT Press


Aleš Filip, Salvatore Sabina & Francesco Rispoli


The Virtual Balise concept has been demonstrated and shared among the ERTMS community as a mean to replace the physical balises by implementing a train Location Determination System (LDS) based on GNSS. It is evidenced both by the results of recent and current EC-supported R&D projects (e.g. 3InSat, ERSAT EAV, STARS, RHINOS, NGTC), the Sardinia Trial Site (Cagliari – San Gavino double track lines) equipped with a ERTMS Level 2 based system with Virtual Balises and the Ansaldo STS Freight SIL 4 ERTMS Level 2 system based on GPS L1 positioning system in commercial service in Australia.

In order to introduce the safe high-integrity LDS system into ERTMS/ ETCS and use it in railway operations in EU member states (MSs), it is necessary to develop and to authorize it according to relevant European and national regulations. It means that this LDS and its integration into ERTMS must pass through a certification and authorization process compliant with the applicable CENELEC standards and EU regulations.

This article deals with a possible certification process of a train LDS as a new subsystem of the ERTMS/ETCS interoperability constituents. Special attention is paid to a possible certification strategy in case of external GNSS safety-of-life service employment via an augmentation network. A possible certification framework for the whole LDS comprising on-board and trackside subsystems is outlined as well. Since the introduction of GNSS into ERTMS/ETCS represents a significant change within EU railway network, then the required common safety method must be applied. In this framework, a new pilot line has been launched by RFI with Ansaldo STS aiming to contribute to the identification of a possible certification process for deploying an ERTMS Level 2, baseline 3 with GNSS localization and public telecom solutions by 2020.


certification, EGNOS, Galileo, GNSS, GPS, railway signalling, safety, safety case