Ensuring data freshness for periodic real-time tasks

International audienceAutomotive systems are composed of embedded applications which are continuously exchanging real-time data. Exchanged data are then propagated within a list of applications involved at different rates in the definition of a function. Different rates of executions for the applications provoke over-and/or under-sampling of data and the age of the data has an obvious impact on the driving decisions. Ensuring that the appropriate data are consumed by an application motivates to maintain the freshness or the temporal validity of real-time data. In this paper we propose a method calculating the freshness of the data for real-time systems where multi-rate sampling of data is considered