This article explains how the National Institute of Standards and Technology (NIST) maintains precise time standards, such as NIST-F1, a highly accurate cesium fountain clock. NIST contributes to the international time scale by providing data to the Bureau International des Poids et Mesures (BIPM). The AT1 scale at NIST is a real-time time scale that combines data from multiple atomic clocks to maintain a stable frequency. UTC(NIST), the time standard used in the U.S., is based on this AT1 scale and is adjusted periodically to stay aligned with the global UTC time scale.
The article also provides details on how UTC(NIST) is calculated in relation to AT1, using specific parameters like time offsets and frequency adjustments. These parameters are updated regularly, usually on the first day of each month, to ensure accuracy. Leap seconds are also accounted for in the calculations. The information is useful for scientists and engineers who need precise time measurements for research or technology applications.
Keywords: frequency standard, cesium fountain, UTC(NIST)
