Replicating UTC(NIST) at Remote Sites

The National Institute of Standards and Technology (NIST) is deploying disciplined oscillators that are referenced to the UTC(NIST) time scale through common-view observations of Global Positioning System (GPS) satellites. We present measurement results from four NIST disciplined oscillators (NISTDOs), three located in the United States, and one located in Concepcion, Chile. These devices replicate the NIST time scale at remote sites, and uncertainties of less than 5 ns are demonstrated at all locations. The results were verified by utilizing the national time scale of Mexico as an independent check standard. Further verification was obtained by directly comparing a NISTDO to UTC(NIST) in Boulder, Colorado.