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Atomic Standards Group

The Atomic Standards group maintains the primary frequency standard, the time scale, and the transfer operations for the U.S. contribution to the International Bureau of Weights and Measures.

The primary frequency standards for the U.S. are currently our two cesium fountains, NIST-F1 and NIST-F2. The time scale is a weighted average of, primarily, hydrogen masers. Two-way satellite time and frequency transfer (TWSTFT) and GPS time transfer are the methods for comparing our clocks with standards around the world for our participation in the generation of international atomic time (TAI and UTC).

News and Updates


White Rabbit-Based Time Distribution at NIST

Joshua J. Savory, Jeffrey A. Sherman, Stefania Romisch
The National Institute of Standards and Technology (NIST) is responsible for ensuring the quality of its international and domestic time and frequency

Use of SDR Receivers in TWSTFT for UTC Computation

Zhiheng Jiang, Victor S. Zhang, Yi-Jiun Huang, Joseph Achkar, Dirk Piester, Shinn-Yan Lin, Wenjun Wu, Sung-hoon Yang, Jerzy Nawrocki, Ilaria Sesia, Christian Schlunegger, Zhiqiang Yang, Miho Fujieda, Albin Czubla, Hector Esteban, Carsten Rieck, Peter Whibberley
Two-Way Satellite Time and Frequency Transfer (TWSTFT) is a primary technique for the generation of Coordinated Universal Time (UTC). About 20 timing


Group Leader (Acting)