High Precision Distributed Time Synchronization with Mobile Atomic Clock Network

The National Institute of Information and Communications Technology (NICT) generates and supplies Japan Standard Time (JST), which is essential to our modern lives, to all regions of Japan. JST is generated by integrating about 20 high-precision atomic clocks, including hydrogen maser clocks, cesium beam atomic clocks, and optical lattice clocks. Current atomic clocks are too large to be portable, but it is envisioned that in the near future, after 2030, smartphones and other mobile devices will be equipped with inexpensive, compact atomic clock chips.

As a joint research project with NICT, Gunma University, Tokyo University of Marine Science and Technology, Seiko Solutions Corporation, and Raidrix Inc, we are conducting research and development of distributed time synchronization technology in anticipation of the widespread use of atomic clock chips. In this research project, by making full use of advanced systems control theory, we will develop a distributed algorithm to achieve ultra-precise time synchronization for a group of atomic clocks whose network structure changes from moment to moment. Specifically

and so forth. Integration of technologies and knowledge in the field of systems control, such as distributed cooperative control, stochastic systems, Kalman filter, maximum likelihood estimation, machine learning, and event-triggered control, is essential for these research and development efforts.

The distributed time synchronization algorithm developed by our research group will be validated through emulation using NICT's comprehensive testbed environment (StarBED4), and then implemented in an actual device with an atomic clock chip developed by Seiko Solutions and others. Ultra-precise time synchronization using a mobile atomic clock network is also positioned as the basis for the realization of Beyond 5G. Deployment areas range from smart grids, financial transactions, broadcasting, and automated driving. Through this research and development, we aim at contributing to the future advanced information and communication society through systems control theory.

Ministry of Internal Affairs and Communications (MIC): R&D for Expansion of Radio Resources

Please contact us if you are interested in working as a post-doctoral researcher.

Research Achievements

Development of Mathematical Foundation for Evaluating Various Time Fluctuations in Atomic Clocks: Contribution to High-Precision Time Synchronization Indispensable for Beyond 5G/6G

Tokyo Tech News (2023.12.20)  Explaining the article "T. Ishizaki, T. Ichimura, T. Kawaguchi, Y. Yano, Y. Hanado: Higher-Order Allan Variance for Atomic Clocks of Arbitrary Order: Mathematical Foundation. Metrologia, 60(1), 2024" [⎋]

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