As a national-level base-type research institute in assuming the tasks of national standard time generating, keeping and transmitting, NTSC, previously called Shaanxi Astronomical Observatory, takes the “Keep close concern with time cycling,

Based on the requirements of economic development for high-precision time service, Shaanxi Astronomy Observatory, Chinese Academy of Science (CAS) was established in the interior of China in 1966, which was renamed National Time Service Center (NTSC), CAS in 2001.

NTSC is a scientific research institution engaging in the fundamental research and technology R & D in the fields of time-frequency and satellite navigation. Aimming at the international science-technology frontier and facing the needs for construction of national time-frequency system and satellite navigation system, NTSC is carrying out a series of scientific activities, such as the fundamental and applied researches in relevant fields, key technology research and system integration. As an important unit participating in establishing the International Atomic Time (TAI), NTSC undertakes the task to generate, maintain and transmit the national standard of time-frequency, and operates a national major scientific infrastructure – the long and short wave time service system.

Focusing on the generation, transmission and application of time- frequency, NTSC is systematically carrying out the researches on quantum frequency standard, measurement and control of time-frequency, time scale and time-keeping, transfer and comparison of time-frequency, time service and monitoring, time service terminal and time-user system, etc., while researching the satellite orbit determination, navigation signal processing and other aspects based on the accumulated researches on time and frequency. Among these, the researches on time-keeping method and time scale, time-frequency measurement, time transfer via satellite, and spacecraft orbit determination, have reached the international advanced level, and the home-made time-frequency equipments have been widely used in various fields.

For more than forty years, a complete time-frequency technology chain has been developed and formed at NTSC, and NTSC has built a national time service system which works by means of telephone, internet, short wave, long wave, satellite, etc., providing a reliable time service with high-precision for many industries and departments. Especially, it has made important contributions to natianal technology development, guaranteeing the successful completion of a series of significant tasks, which has been praised and rewarded for many times by the State Council of PRC and relevant. NTSC has won more than 150 significant scientific achievement awards at provincial level or above, of which the construction of BPL long-wave time service system won the First-rank of National Science and Technology Progress Award. Like a dozen of other important laboratories in the world, NTSC has maintained an independent atomic time, TA (NTSC). For recent years, NTSC’s contribution in terms of weight, and the comprehensive performance indicators such as the long-term stability of the local coordinated universal time (UTC (NTSC)), have been in the top five among the world's 72 time-keeping laboratories which participate in establishing TAI. Additionally, the research achievements in communication satellite-based navigation have been highly appraised by the leaders of CCP and state.

There are 450 on-the-job staff members at NTSC, of which more than 60% hold master degree or above. The main scientific units include seven laboratories, one time-keeping laboratory, one time service division, as well as a CAS key laboratory in time and frequency standards, and a CAS key laboratory in precise navigation and timing technology. NTSC possesses some research platforms and systems with domestic or international advanced level, such as the quantum frequency standard research platform, system for time-frequency comparison & measuring, system for generating and maintaining of national standard time, system for generation and comparison of national joint atomic time, two-way satellite time comparison system for China-Japan link and China-Europe link, international satellite all-in-view time-frequency comparison system, low-frequency time code time-service station, timestamp network service system, national major science infrastructure - long and short wave time service system, optical fiber time-frequency dissemination system, satellite time-service experiment system, platform for research, development and production of time service terminal and time-user system, and has a set of satellite navigation experimental system including master control station, orbit-determining station, etc., as well as a set of system with a large-aperture antenna for monitoring and evaluating the quality of satellite navigation signals. Besides, the library houses more than 40,000 books and some main databases and electronic journals in related specialties purchased at home and abroad, while two open database, one for time-frequency science and another for international satellite navigation, have been established.

NTSC conducts three doctoral-student training programs in specialties of information & communication engineering, astrometry & celestial mechanics, and measurement technology & measuring instruments, and five postgraduate-student training programs in specialties of astrometry & celestial mechanics, measurement techniques & measuring instruments, communication & information systems, Measuring and Testing Technologies and Instruments, and electronics & communication engineering, as well as a post-doctoral research program in astronomy, with about 150 graduate students studying at NTSC.

With some employees serving in the international academic organization, NTSC keeps constant cooperation with more than 30 international advanced research units on time-frequency and satellite navigation, including the International Bureau of Weights and Measures (BIPM), Physikalisch Technische Bundesanstalt (PTB), Observatoire de ParisMeudon (OP), National Physical Laboratory (NPL), National Institute of Information and Communications Technology (NICT), Massachusetts Institute of Technology (MIT), German Research Centre for Geosciences (GFZ), etc.. On behalf of China, NTSC participates in the cooperation in TAI calculation. NTSC is the head unit of the Chinese counterpart working group which corresponds to the time-frequency working group of International Telecommunication Union (ITU), and NTSC is also a member unit of working group of Two-way Satellite Time and Frequency Transfer (TWSTFT), as well as the deputy-head unit of the international cooperation group of Chinese global satellite navigation and positioning system. NTSC publishes Journal of Time & Frequency and Time & Frequency Bulletin, and operates a "National Top Ten Outstanding Science Website" - "www.time.ac.cn".

Address: No. 3, East Shuyuan Road, Lintong District, Xi’an City, Shaanxi Province, 710600;

Contact person: Cao Yubo, senior engineer

Tel.: 029 – 83890326;

Fax: 029 – 83890326

E-mail: office@ntsc.ac.cn