Decentralized vehicle-mounted Safety Logic for Secondary Railway Lines based on GNSS Positioning and Integrity Monitoring

Railway operation is based on various safety critical control and signalling operations which are conventionally realized by stationary infrastructure. Acquisition, maintenance and operation of these components are generally very cost-intense and compromise the future of railways lines with low traffic volumes. These so called secondary railway lines are essential to satisfy mobility requirements especially in rural regions and differ from conventional main routes as they provide several operational characteristics (e.g. single-laned) which enables simplified, decentralized administration of route setting and train movements. In the work presented, a general overview of a vehicle-mounted safety logic concept which includes a detailed description of the essential probabilistic multisensor GNSS based train position estimation module is suggested. The localization and tracking is performed by adopting an Extended Kalman Filter (EKF). Additionally, a Fault Detection (FD) Receiver Autonomous Integrity Monitoring (RAIM) for safety critical applications is used to ensure integrity of the estimated positions. The GNSS parts of the developed localization and integrity module are validated using a real world Software Defined Radio (SDR) recorded GNSS-RF-dataset which is played back in a laboratory environment enabling reproducable validation cases with different GNSS receivers and algorithm parametrizations.