The NIST Special Calibration Test, Preliminary Results and Future Plans

We will present the first results of the NIST Special Calibration Service, a collaboration between the Time and Frequency Division of NIST and OPNT. The service is defined as the realization of time transfer from UTC(NIST) to a commercial time-distribution location with an initial accuracy of 1 µs and an ultimate accuracy of 100 ns after 6 months of operation. To accomplish involves the placement of time-delivery equipment within a NIST location, connected from there via optical fibers to the time-delivery equipment at the commercial distribution site, independent of external signals in general and the signals from GNSS satellites in particular. This first service case is implemented over dedicated optical fibers between the NIST reference time scale at the NIST facility in Gaithersburg, Maryland and the OPNT commercial location in McLean, Virginia. There sub-nanosecond stability has been demonstrated, well within the accuracy targets. Further, connectivity has been extended from McLean to Atlanta, Georgia, and back, over 1,600 fiber miles. There preliminary data shows sub-microsecond stability, consistent with national targets in support of U.S. critical infrastructure. We are currently planning for a second set of links between the NIST time scale at the NIST facility in Boulder, Colorado and Silicon Valley, California, along with other locations between Boulder and McLean. We will discuss the designs of these links and present the results of the ongoing calibration tests.