Table of Contents
International Journal of Navigation and Observation
Volume 2008 (2008), Article ID 841672, 7 pages
Research Article

The New Generation System of Japan Standard Time at NICT

1Space-Time Standard Group, New Generation Network Research Center, NICT, 4-2-1 Nukui-Kitamachi, Koganei, Tokyo 184-8795, Japan
2National Institute of Information and Communications Technology, (NICT), 4-2-1 Nukui-Kitamachi, Koganei, Tokyo 184-8795, Japan
3Incubation Department, Core Technology R & D Center, ANRITSU Corporation, 5-1-1 Onna, atsugi, Kanagawa 243-8555, Japan

Received 30 July 2007; Accepted 15 January 2008

Academic Editor: Demetrios Matsakis

Copyright © 2008 Yuko Hanado et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


NICT has completed a set of major upgrades in its systems for the realization of Japan standard time. One of the most significant changes is the introduction of hydrogen masers as signal sources for UTC (NICT) instead of Cs atomic clocks. This greatly improves the short-term stability of UTC (NICT). Another major change is the introduction of a newly developed 24-channel dual-mixer-time-difference system (DMTD) as the main tool for measurements. The reliability of the system is also improved by enhanced redundancy and monitoring systems. The new JST system has been in regular operation since February 2006.