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Chinese BeiDou Satellite Creates “Two Big Nets” for Ground and Space
Updated:2018-07-25
2018 is the “big year” for the Chinese BeiDou satellite network. 6 BeiDou-3 satellites were already launched and about 10 more are to be launched by the end of this year, to provide service for countries concerned with the Belt and Road. In addition to weaving the BeiDou satellite network in space with global coverage, China is also working hard to build a ground reinforcement network that can achieve centimeter and millimeter positioning accuracy, to better apply high precision space-time information in different levels of society. With regard to the construction of the two big nets and changes to be brought to the BeiDou application after its completion, reporter interviewed a number of leading experts in the navigation area in China.
The “Big Net” in space is taking shape.
Spokesman from the administration office of Chinese BeiDou Navigation Satellite System introduced the BeiDou in detail network during the 9th China Satellite Navigation Conference (CSNC). He said that it has been 5 and half years since BeiDou-2 system was built and commissioned. The system has maintained stable and reliable operation with service performance satisfying requirements of the anticipated indicators. Its service never stopped halfway and its positioning accuracy was raised from 10 meters to 6 meters. In order to ensure steady and smooth running of BeiDou-2 and steady improvement of its service performance, two more BeiDou-2 backup satellites will be launched in the next two years.
China’s accelerating the progress of BeiDou-3 Network is drawing wider attention. In the November of 2017, January, February and March of 2018, China has successfully launched four sets of BeiDou-3 satellites, 8 in total, in less than six months. The spokesman revealed that about 10 more BeiDou-3 MEO satellites and 1 GEO satellite will be launched in 2018, achieving the ability of global service in 2020. At present, in-orbit test, system integration and performance appraisal of networking satellites are under way. Preliminary results showed that the satellites are running in favorable in-orbit conditions and their performance meets the requirements of indicators. The in-orbit test demonstrated that the user range error of spatial signal was expected to reach 0.5 m and the system positioning accuracy to reach 2.5 m to 5 m.
It is understood that BeiDou-3 is fully compatible with BeiDou-2 in terms of technological system and has upgraded performance and extended services. During the transitional process from BeiDou-2 to BeiDou-3, frequent users can freely adapt to it and new users can enjoy improved performance, eventually replacing the old technologies with the new ones.
“The Last Kilometer” of Ground Precision Navigation
Drivers in the city often encounter an awkward situation when using the navigation apps: it will show that the car is on the side road, while the car is actually on the main road. Moreover, in relatively complicated situations such as the tunnel and overpass, the navigation tends to be inaccurate. To solve this pain point, simply by launching more satellites and improving single-satellite performance are not enough.
The fundamental solution lies in the construction of a ground network that can improve the positioning accuracy significantly. Cai Yi, Chief Product Engineer of the National BeiDou Foundation Augmentation System and chief scientist of China North Industries Group Corporation Limited, recently said in an interview that China is constructing the BeiDou foundation augmentation system in different stages; currently, the construction developed from the first stage has officially passed the national standard in June, 2017, including the base station network system formed by 1,355 base stations, the National BeiDou Foundation Augmentation System Comprehensive Data Processing Center, 6 industry data processing branch centers: homeland resource, transportation, the Chinese Academy of Sciences (CAS), earthquake, meteorology, and surveying, mapping and geoinformation. The construction of the “One Net for the Whole Country” of BeiDou foundation augmentation system, which is capable of autonomous control, is preliminary completed. It provides nation-wide, real-time precision positioning services of meter and sub-meter levels, and for the central and eastern regions such as Beijing-Tianjin-Hebei, Yangtze River Delta, Pearl River Delta and other 17 provinces and cities, it provides real-time high-precision services of centimeter and post-processing millimeter levels, achieving “countless BeiDou in the space, one foundation net on the ground”.
The spokesman also revealed in the annual meeting that, by 2035 if possible, China will build a national comprehensive positioning, navigation and timing system of high precision, safety and reliability.
Moreover, with its seamless coverage of the space, ground and sea, as well as the interconnection and intelligence of everything, the capability of space-time information service will be substantially reinforced.
What is the Distance between BeiDou and Our Lives?
In mentioning the scale of the BeiDou application, the authority enumerated a series of statistics: the scale China’s satellite navigation industry is expected to exceed 400 billion yuan by 2020, with BeiDou pulling market share of 250-320 billion yuan. Currently, there are 5 million operating vehicles are launched, building the world’s largest Internet of Vehicles (IoV) platform. More than 40,000 fishing vessels are equipped with BeiDou, cumulatively helping over 10,000 fishermen. Meanwhile, BeiDou applications designed for the general public are easily accessible and increasingly immersed in people’s lives. Shared bicycles equipped with BeiDou are capable of precision management. Watches, bracelets and student cards supporting BeiDou are also making daily life more convenient. Take Beijing as an example. There are 33,500 taxis and 21,000 buses equipped with BeiDou, realizing full coverage of BeiDou positioning; and there are 1,500 logistics trucks and 19,000 delivery staff using BeiDou terminals and bracelets to access to logistics cloud platforms, realizing real-time dispatch.
In daily travels, people are more and more accustomed to use navigation apps in route planning. What role does BeiDou play in daily navigation? Xie Jun, the vice chief designer of BeiDou Navigation Satellite System, told the reporter that it is actually hard to whether a certain navigation and positioning application scenario is using BeiDou or GPS; general users of navigation apps normally pay less attention as to which satellites are providing signal, than the use experience. Xie Jun believes firmly that, with the steady improvements of BeiDou-3 and single satellite, and the complementing foundation augmentation system becoming increasingly mature, without being noticed by the domestic users, the probability and weight of BeiDou’s role will be bigger, Chinese telecommunication expert Xiang Ligang introduced to the reporter on May 23 that most mainstream mobile phone manufacturers both domestic and international are using chips compatible with BeiDou, and “compatible interoperability has become the industry consensus”. A related insider revealed to the reporter on May 23 that basically all the mobile phone chips of manufacturers both domestic and international are now compatible with BeiDou system. This expert said that, when choosing satellite in navigation and positioning, it is not a matter of exclusiveness, but the more the satellites available, the higher the positioning accuracy. Being compatible with multiple satellite navigation systems reduces greatly the blind spots of single satellite navigation system, mitigating the problem of navigation signal loss caused by urban building blockage and other elements and increasing the continuity of satellite navigation system service.
