Precision Time Protocol (PTP) Using LinuxPTP on Single Board Computers

Precision time, traceable to Coordinated Universal Time, is a requirement for some power grid applications. Accuracy in milliseconds (10
⁻³
) is achievable using Network Time Protocol over wide area networks. Accuracy in microseconds (10
⁻⁶
) is achievable using GNSS as a basis for time synchronization and this is a minimum standard for some applications. However, satellite signals are easy to jam over wide areas. Precision Time Protocol (PTP) may provide an adequate source of precision time over wide area networks. For it to be utilized, uncertainty in measurement must be quantifiable and a range of network design constraints are required to match the application. In this paper, an inexpensive test bed is constructed and tested, and initial measurements are made of precision.