China's Beidou navigation timing system advances time synchronization of 5G networks
As we all know, the satellite navigation timing system, as an important space information infrastructure of a country, can provide precise positioning and precise timing functions. It is of extremely important strategic significance for national defense, social production, and daily life. It is also a guarantee basis for national autonomy and security.
The Chinese government attaches great importance to the development of the Beidou system. Since 2016, under the joint promotion of the Central Cyberspace Administration of China, the National Development and Reform Commission, the Ministry of Science and Technology, the Ministry of Industry and Information Technology and other departments, the Beidou precise positioning and timing functions have been used in agriculture, industry, police, and Various industries and fields such as surveying have been gradually developed, and have continued to mature and deepen.
It is reported that the draft of the Regulations of the People’s Republic of China on Satellite Navigation, which was drafted by the central and national ministries and commissions, enterprise/association expert representatives, and important users such as civil aviation, electric power, public security, and communications, has been initially completed. The regulations will be strengthened through the rule of law. Top-level design and overall development of satellite system related services. It can be predicted that with the promulgation and implementation of the regulations, the Beidou system will be more deeply integrated with all walks of life and our daily lives, and the large-scale application of Beidou and the route towards internationalization will become clearer.
China's Beidou navigation timing system can be divided into three generations as a whole:
The first generation, deployment time: October to December 2000. 2 2 (spare) satellites are active area satellite navigation systems. Its service range is domestic; positioning accuracy is 20 meters; timing accuracy is 100 nanoseconds.
The second generation, deployment time: 2007 to 2012. It is composed of 14 Beidou-2 (5 geostationary orbit navigation satellites, 5 tilted geosynchronous orbit navigation satellites and 4 medium-circle earth orbit navigation satellites), which is a combination of passive and active regional satellite navigation systems. Its service range is the Asia-Pacific region; positioning accuracy is 10 meters; velocity measurement accuracy is 0.2 m/s; timing accuracy is 50 nanoseconds.
The third generation, deployment time: From 2017 to 2020, 35 Beidou-3 navigation satellites will be launched successively (5 geostationary orbit satellites, 3 tilted geostationary orbit satellites, 27 mid-circular orbit satellites), which are passive and active Integrated global satellite navigation system. Its service range is global; positioning accuracy is 2.5 to 5 meters; speed measurement accuracy is 0.2 m/s; timing accuracy is 20 nanoseconds. By then, the positioning and timing accuracy of the "Beidou" will be completely comparable to or even better than that of the US GPS.
In addition, my country’s Beidou third-generation system also has some performance and features that the US GPS, Russian GLONASS and European Galileo navigation systems do not have, such as communication and short message capabilities, inter-satellite link capabilities, high-precision hydrogen atomic clocks (improved clock stability) 10 times), two-way timing, satellite autonomous navigation, three orbit satellite combinations, etc. The combination of the three orbiting satellites has stronger anti-blocking ability than other satellite navigation systems, especially in low latitude areas, which greatly improves the seamlessness of coverage and the credibility of security. The inter-satellite link is the key to "Beidou" to realize autonomous navigation. The so-called autonomous navigation means that under extreme conditions, all ground stations fail. 35 "Beidou" navigation satellites can be calibrated through the inter-satellite link to ensure reliable operation of the entire constellation. , Without interruption of precise positioning and timing services, this is equivalent to providing more insurance for the all-weather, all-day, high reliability, and high precision of the Beidou system. In addition, Beidou's unique two-way timing function can greatly improve timing accuracy, and can play a key role in some special occasions.
With the large-scale construction and popularization of 4G networks in recent years, my country's mobile communications industry has ushered in rapid development. According to the latest official data from the Ministry of Industry and Information Technology, the total number of mobile communication base stations in my country has exceeded 6 million. Among these base stations, apart from some systems that do not require precise timing due to technical system reasons, most of the other base stations currently rely on GPS for timing. For example, the TD-LTE 4G mobile communication system, which has the paradigm significance of my country's independent innovation, requires a system time synchronization of 1.5s. However, due to historical and other reasons, almost 100% use the US GPS system for timing and synchronization.
It is conceivable that a network and system that completely relies on the US GPS will have greater risks and uncertainties in its safety and reliability. We have also noticed that phenomena like GPS disturbance and interference that affect the normal operation of the communication system also occur from time to time, and similar reports are not uncommon. The recent occurrence and see-saw-style progress between China and the United States has even more affected the nerves of the people's autonomy and security, and has also triggered a lot of thinking.
The Beidou system has been fully practical. According to incomplete statistics, the scale of Beidou-related industries has reached 300 billion, and the cumulative application of Beidou terminal products has exceeded 40 million. In 2018, a total of 18 navigation satellites will be launched and invested in the year. Operation, priority is given to ensuring high-precision navigation and timing requirements in domestic and related areas of the Belt and Road Initiative. Therefore, using Beidou to replace GPS to provide base station timing and synchronization services is not only completely feasible in terms of technical principles, application effects, and economic benefits; it is also imperative from the perspective of the independent, safe and reliable strategic requirements of national information infrastructure. .
As a new generation of mobile communication networks, whether in Europe, America, Japan, South Korea or China, from the national government to the operator level, the development of 5G is attached great importance, and related experiments and industrial advancement are in full swing. Not only does 5G make the mobile Internet more bandwidth and faster, its other two features, "low latency, high reliability," and "massive links" will have a more profound impact. 5G can realize the true interconnection of all things, and it is also the most important strategic foundation for realizing the digital transformation of the national economy and the 2025 goal of industrial manufacturing.
The conventional time synchronization requirement of 5G network is still 1.5s, which is not much different from 4G. However, with the development of network technology and the application needs of special application scenarios, a higher requirement of 130ns is also proposed. However, it is obvious that even the 130ns requirement can be easily dealt with by Beidou II or Beidou III. The large-scale commercialization of 5G is expected after 2020, when the powerful, safe and reliable Beidou three generations have also been completed, and the application of Beidou in the 5G network is a matter of course.
As a high-speed and efficient basic information network that is vital to the country and society, 5G's autonomy and security are self-evident. From the perspective of network synchronization and base station timing alone, the use of Beidou system or Beidou/GPS dual-mode to replace a single GPS system needs to be put on the agenda as soon as possible and put into practice. In the future 5G scale-up trials and NDRC 5G demonstration city projects, Even in full commercial use in 2020, the application needs to be firmly implemented and promoted!