High-resolution time synchronization over SpaceWire links

We have demonstrated the benefits of the high-resolution extension to the SpaceWire standard. Initially limited to 280 ns, we are able now to achieve a time-tagging accuracy of 40 ns, which represents a gain by a factor of seven. When in the free-running counter configuration, the highest time resolution could still be achieved even with low SpaceWire data rates. In that case, the time resolution is dramatically increased with our extension with respect to the standard; e.g., the gain is 35 for a data rate of 10 Mbps and a 100-MHz free running counter. As mentioned, the footprint of the extension stays very limited, which allows an easy implementation in any space FPGA. Such an extension combines the benefits of the SpaceWire standard and high-resolution time tagging without the need for another dedicated interface for clock and synchronization signal distribution.