On-line timestamping synchronization in distributed sensor architectures

This paper describes a solution for online timestamping in a distributed architecture embedded in an experimental vehicle. Interval timestamping is used, taking into consideration sensor latency, transmission delay and clock granularity. This solution does not change local system clocks, so that the network configuration can change without affecting timestamping precision. All nodes of the network are connected via a synchronous bus network (here, the FireWire, IEEE 1394). The bus clock is used to estimate the drift of all computer clocks and to exchange data timestamps with high precision. Experimental simulations show the advantages of this solution. The method is well adapted to dynamic applications, where data timestamping is important for real time considerations. An application in the field of intelligent vehicles is then described.