Today, railway operators typically use GSM-R as train-based telecommunications infrastructure to exchange information such as movement authorities and position reports between a control centre (Radio Block Centre, RBC) and a train computer (European Vital Computer, EVC). GSM-R is a railway-specific adaptation of the GSM standard and requires its own network infrastructure.
Such ground-based infrastructure requires significant up-front investment and is expensive to maintain, but typically yields poor return on investment on lines with low utilisation volume (such as regional lines). Deployment might be virtually impossible in remote areas without power grid and lack of any communications infrastructure.
TriaGnoSys is responsible for the design and implementation of a hybrid telecommunications framework, combining satellite and terrestrial-based bearer services.
Requirements for this novel communication system are defined based on existing GSM-R requirements, and are also taking into account specifics of future applications and services. System and hardware components are selected based on those requirements and based on environmental requirements of the railway environment.
For the purpose of the technology evaluation and demonstration, data traffic between control centre and train is emulated through purpose-built software-based traffic generators. These software emulators allow flexible emulation of different traffic profiles, including extreme cases.
A number of different traffic profiles have been defined that resemble typical operational scenarios. The emulated traffic is routed either through the terrestrial network or through the satellite network.
Each traffic profile is run for a considerable amount of time to gain statistically significant data. The data traffic emulation framework measures network characteristics such as one-way packet delay, packet jitter and loss as well as effective bitrates.
Measurements are taken in a stationary lab environment as well as in a real train environment. The newly designed communication equipment is temporarily installed on a train for that purpose. The test train is operated on a 50km test track in Sardinia, Italy.
The data gathered during these trials are characterised and used as input for a safety analysis. This analysis evaluates the application of satellite- and terrestrial networks in safety critical train applications with the overall aim to increase public safety on railways while reducing capital expenditure through the use of cost-effective communication solutions.
The 3InSat project is partly funded under part 20 of the ‘Advanced Research in Telecommunications Systems’ (ARTES) programme, sponsored by the European Space Agency (esa). ARTES 20 is dedicated to the development, implementation and pilot operations of Integrated Applications. Project members are Ansaldo STS (Italy), Radiolabs (Itlay), AŽD Praha (Czech Republic), TriaGnoSys (Germany), Rete Ferroviaria Italiana (Italy), DLR (Germany).