Abstract
This paper presents the concept for reliable vehicle-autarkic collision detection developed for a Rail Collision Avoidance System (RCAS) that is based on direct train-to-train communication. Similar to existing systems inair and maritime transport, the RCAS approach allows vehicle-autarkic detection of imminent collisions. Designed as a safety overlay system, it shall warn and advise train drivers in such situations. Broadcasted messages shall allow each railway vehicle to assess the traffic situation in its vicinity under all operational conditions. Apart from an onboard localization unit, which relies on satellite navigation signals, the system architecture does not require any other infrastructure.