Target measurements influence on level crossing detection system safety assessment

The design of critical to safety systems is usually approached through the observation of specific standards which are applicable in the field of interest of the considered application itself. Even if, most of time this kind of design orientation can be satisfactory to address the majority of problems, sometimes it may lead to tricky situations where some crucial aspects can be neglected. This risk is high when new sensors or new system applications are designed because some hidden hazards can be related to the sensor physics or to the specific considered scenario as well. In this paper the authors discuss how the implementation of a peculiar application for level crossing monitoring (LC) based on a specific radar technology can be jeopardized if sharp analysis of the target to be detected is not performed. The possibility to exploit single sensor or multi sensor solutions is proposed discussing the advantages and pitfalls of the different designs in terms of system reliability, availability and safety. Considerations about measurement uncertainty depending on the type and orientation of the object to be detected is presented on an empirical basis as well.