China finishing “High-precision Ground-based Timing System”
Two recent announcements showed China’s progress establishing its national “High-Precision Ground-based Timing System.” Some verbiage in the most recent announcement could indicate that the system is nearing completion.
The timing system is designed to support a vast array of scientific and technological applications as well as provide services when space-based signals are not available.
According to some Western observers, it is another example of China’s increasing lead over the United States in positioning, navigation, and timing (PNT) technology.
Its BeiDou satellite PNT system is newer and has been acknowledged superior in many ways to the U.S. Global Positioning System (GPS). This has allowed China to gain influence in some parts of the world at the expense of the United States.
Completion of the terrestrial system could have even more troubling implications for the United States.
Recent Announcements
On May 21 this year, a government affairs article in Shaanxi’s “The Paper” announced accelerated construction in Xi’an of a science center. Its centerpiece will be the country’s High-precision Ground-based Timing System. It is not entirely clear from the article whether this site will be the engineering and administrative headquarters for the system, or one of several “timing stations.”
The article also says the national system will be the largest in the world — with more than 20,000 kilometers of optical fiber and 295 time and frequency transmission sites — and will integrate space- and ground-based signals.
The network, according to the article, will supplement and improve the new eLoran (sometimes mistranslated by software as “Roland”) system in the western portion of the country. It will also support legacy eLoran “long-wave” signals in the east ensuring that the entire nation is well served.
Accuracy for the system’s fiber-optic transmissions is claimed to be less than 100 pico-seconds, with differential eLoran at less than 100 nanoseconds.
Experts in the West have confirmed that both these goals are achievable. Europe’s CERN laboratory has demonstrated picosecond level via fiber, and UK trials have shown the accuracy of differential eLoran to be within 50 nanoseconds.
A much shorter press release was issued on June 8, announcing groundbreaking for a “timing station” in Nagqu on the Tibetan plateau in China’s west. The announcement said that, once the station was complete, China will “…realize national soil coverage of long-wave [eLoran] timing signals…”
Expansion of its eLoran and fiber infrastructure to serve the entire nation gives China what some have called the “PNT resilience triad” — signals from space, from terrestrial broadcast, and over fiber. The three sources of delivery are sufficiently different that an accidental or malicious disruption of one is highly unlikely to impact the other ones. Users accessing all three should experience minimal to no impact.
Both the May and June announcements said that finishing the timing project will benefit China’s national economy and national security.
Timing is essential tech infrastructure. More precise and robust timing enables improvements to current applications and the creation of new ones. For example, better timing can enable greater spectrum efficiency with more throughput on existing frequency bands. Highly precise fiber-based timing could also support using 5G telecommunications networks for hyper-precise positioning in autonomy corridors serving self-driving vehicles, UAVs, and other systems.
China’s ground-based timing system is part of a larger plan by its National Timing Service Center for a system of systems approach to PNT. Described as a “comprehensive approach” at the Standford PNT Symposium in 2019, the architecture has satellite-based navigation at its heart and includes a wide variety of other capabilities.