The Dunhuang Longwave Timing Station, part of the high-precision terrestrial timing system – a major national scientific and technological infrastructure undertaken by the National Time Service Center of the Chinese Academy of Sciences, was announced to be completed and successfully tested on the 30th, marking another step forward in the construction of China's three-dimensional time service system that integrates space and ground.
The Dunhuang Longwave Timing Station is located in the northeastern part of Dunhuang City, Gansu Province, and is a key component of the national high-precision terrestrial timing system developed during the 13th Five-Year Plan period.
Zhang Shougang, director of the National Time Service Center, explained that the high-precision terrestrial timing system utilizes both enhanced Roland radio longwave timing technology and high-reliability, high-precision fiber-optic timing technology. It is designed to operate independently, provide backup, complement, and enhance the satellite navigation timing, thus establishing a comprehensive, unified, traceable, secure, and advanced national timing system in conjunction with other existing timing systems. This enhanced system better supports the operation of the economy and society and contributes to the technological advancement and national security.
It is reported that longwave timing is currently the most reliable terrestrial timing method. By establishing three additional longwave timing stations in Dunhuang, Xinjiang's Korla, and Tibet's Naqu, in conjunction with existing facilities, China can achieve nationwide coverage of longwave timing signals.
During the construction of the Dunhuang Longwave Timing Station, researchers overcame challenges related to high-precision broadcasting control and pulse time reference feedback modulation technology, as well as high-stability, high-power pulse signal generation technology. They achieved a timing broadcast precision of 20 nanoseconds with megawatt-level Roland transmission, surpassing the existing international standard of 50 nanoseconds. By utilizing differential enhancement information, users can improve timing accuracy from the microsecond range to the nanosecond range.
The national timing service requires continuous, safe, and reliable provision of high-precision national standard time signals to users across varying spaces, conditions, and needs, utilizing various technological means 24 hours a day. Zhang Shougang noted that after nearly 60 years of development, China has established the world's most advanced national timing system, improving timing accuracy from the initial millisecond level (one-thousandth of a second) to the current level of hundreds of picoseconds (hundred billionths of a second), achieving a seven-order magnitude improvement, placing it at the forefront globally and effectively meeting national needs.