A Reliable and Self-Aware Clock for reference time failure detection in internal synchronization environment

A reliable source of time is a fundamental requirement for safety critical applications. For this class of applications, synchronization protocols like the IEEE1588 standard, can be adopted. This type of synchronization protocols was designed to achieve very precise clock synchronization, but they may not be sufficient to ensure safety of the whole system. For example an instability of the local oscillator of a reference node could influence the quality of synchronization of all nodes. In the recent years a new software clock, the Reliable and Self-Aware Clock (R&SAClock), which is designed to estimate the quality of synchronization through statistical analysis, was developed and tested. This paper describe and evaluate the design of a protocol for timing failure detection for internal synchronization based on a revised version of the R&SAClock software suitably modified to cross exploit the information on the quality of synchronization among all the nodes of the system.