Objective(s):

•Implementation of a GNSS simulation testbed including software and interfaces to RF generation equipment, train motion model, tools for modelling of nominal railway environment and injection of feared events (originating from system & local environment), and tools to evaluate performances against generated ground truth

•Definition and development of PNT candidate architectures to be assessed using the testbed

Background and justification:

•The railway simulation testbed is an essential tool / capability needed to support validation of GNSS receiver technologies / techniques / integrity algorithms for safety-related applications in railway

•Testbed complements field testing allowing conditions that are statistically unlikely to be observed in the field to be simulated in a highly controlled and repeatable environment

Achievements and status:

•Development of GNSS Feared event models and implementation for simulation to support fault-injection testing

•Support for simulation of signal distortion feared events (threat models in DO229F)

•Tools to define scenarios via GUI including nominal railway environment (use of railway-specific multipath channel model) and injection of specific feared events

•Support for simulated sensor outputs (including ETCS odometry)

•Support software generation of baseband samples and generation of RF signal with dual GSS9000 setup (incl. vector signal generator and ICU for interference)

•Testing of candidate PNT architectures using Sim4Rail testbed (Hitachi STS product and several PNT platforms developed during activity: baseline + architectures using sensors, ARAIM, filter-banks, etc.)

Benefits:

•Benefits of this testbed include the capability to perform testing of railway GNSS equipment under both nominal and extreme conditions in the laboratory, including support for fault-injection testing. Sim4Rail provides a modular testbed with well-defined interfaces, allowing users to perform testing and evaluate performances at different levels from algorithms to hardware in the loop.