The National Institute of Standards and Technology (NIST) now offers a service that provides customers with an oscillator locked to UTC(NIST), the United States national standard for frequency and time. A NIST disciplined oscillator (NISTDO) works by utilizing both the Internet and common-view observations of Global Positioning System (GPS) satellites, and can serve as the primary frequency and time standard for a calibration or metrology laboratory. NISTDOs are directly referenced to the Coordinated Universal Time scale kept at NIST, known as UTC(NIST). This makes it easy for laboratories to establish traceability to the International System (SI) directly through NIST. Customers are provided with standard frequency outputs of 5 MHz and/or 10 MHz, as well as 1 pulse per second timing outputs. These outputs provide time with an uncertainty near 10 ns with respect to UTC(NIST) and provide frequency with an uncertainty of less than 5 × 10-14 when averaged over a 24-hour interval. This paper discusses the theory of operation of the NISTDO, and demonstrates the accuracy and stability of the device over both short and long time intervals. It also discusses possible future applications of NISTDO technology.
Citation: Measure: The Journal of Measurement Science
Pub Type: Journals
disciplined oscillator, GPS, Internet, time scale, time transfer