If you want the go under the nanosecond there is the White Rabbit [1][2] project. The CERN uses it to control the magnets in the loop of a particule accelator. It is also based on NTP, Ethernet and FPGA.

[1]: http://www.ohwr.org/projects/white-rabbit

[2]: https://en.wikipedia.org/wiki/White_Rabbit_Project