The “Space-Ground Integrated Information Network” (tiandi yitihua xinxiwangluo, SGIIN) is an “Engineering Mega Project” approved by China under its 13th Five-Year Plan (2016-2020) in March 2016. Like other mega projects, this project reflects China’s “national strategic intentions”, with the specific aim of “promoting the integration of spatial information networks, future Internet and mobile communication networks” by 2030.
The concept behind the SGIIN is not unique to China. The United States Department of Defense, for example, developed similar networks such as the Global Information Grid and the Transformational Satellite Communications Systems in 2007 and 2008 respectively, which integrate space and ground networks for military purposes. China’s development of such integrated networks appears to be lagging behind US military programs, although it first mentioned plans to develop a space-to-ground integrated network system in a 2000 white paper.
Nevertheless, given the significant implications of the SGIIN project on China’s overall economic and military capabilities, it is important to take stock of the project’s developments and achievements to date, particularly after the recent conclusion of the period of the 13th five-year plan.
Background and concepts
The SGIIN project is led by the China Electronics Technology Corporation (CETC), a public Fortune Global 500 company, which leads China’s cyber research, among many fields. Essentially, the SGIIN is designed as a unified system that interconnects space and terrestrial networks to provide secure, on-demand network services to maritime, land, air and space users worldwide.
Space networks typically include a space segment and a ground segment. The Space Segment of the SGIIN Space Networks consists of satellite nodes in Geostationary Earth Orbit (GEO) (less than 35,000 km from Earth) and in Low Earth Orbit (LEO) (500-2,000 km from Earth) . Six satellite nodes in GEO would form the backbone network while the access network in LEO has a planned constellation of 60 hybrid satellites and 60 broadband satellites connected by inter-satellite links.
The ground segment of space networks is composed of interconnected ground nodes, including gateway stations and information ports, which are connected to both satellite nodes (in space) and ground networks (on Earth) (i.e. mobile communication networks, wireless Internet). Basically, the availability of space networks in the SGIIN saves China from building a large network of ground stations globally, so only a few local ground stations would be needed to establish global coverage.
CETC’s work on the SGIIN is based on close collaboration with other local institutes. In January 2018, it established a joint lab with Tsinghua University to research key technologies; in May 2018, it founded a joint innovation center with Zhijiang laboratory; in late 2018, he brought together a coalition of more than 40 research institutes, universities and industry players with an information network and aerospace expertise to carry out the high-level design, standard formulation and SGIIN Technical Research.
The CETC also runs the SGIIN Hefei Center, which houses the SGIIN Research Institute (Anhui). Inaugurated in December 2018, the research institute is a collaborative innovation base focused on the development of key technologies, including LEO satellites, floating platform communications, space computing and the integration of information into space, among others. Also in December 2018, CETC and the Institute of Microsatellite Innovation of the Chinese Academy of Sciences signed a cooperation framework agreement to build a pilot test network of the satellite node of the space backbone.
The CETC is also responsible for the construction of the SGIIN ground information ports, responsible for the aggregation and processing of all types of remote sensing, meteorological and satellite navigation data to provide information services to the government, public and private companies. In March 2019, the SGIIN ground information port prototype system was officially launched for online trial operation, and five more were reportedly launched by the end of 2019.
A milestone was reached in June 2019, when China launched Tianxiang 1 and 2, a pair of experimental satellites representing the unitary model for building the space access network. The two satellites successfully carried out various technological experiments for the first time, including the transmission of space network information, inter-satellite measurement, navigation enhancement, and aviation and navigation monitoring from the space.
Potential military implications
While the SGIIN ostensibly aims to serve national economic and social development goals, China’s military-civilian fusion strategy would most likely take place in the SGIIN. Professor Li Deren, an eminent scientist in photogrammetry and remote sensing, pointed out that the construction of a space-based real-time service system, integrated with the functions of positioning, navigation, timing, remote sensing and communication , is crucial for civil and national security needs. Similarly, Professor Yin Hao, a communication expert and director of the People’s Liberation Army Military Science Academy (systems engineering department), advocated building an integrated system that provides satellite navigation and remote sensing for military and civilian use.
With respect to potential military implications, the SGIIN would improve situational awareness in all domains by connecting ground and non-ground (airborne, space-based) sensor networks, command networks, and tactical information distribution networks. . Although the People’s Liberation Army (PLA) has existing C4ISR networks such as “Qu Dian” and the “Joint Information Distribution System”, its satellite resources from existing remote sensing, navigation and communication satellites are underutilized and have not been effectively exploited for joint operations. operations. Its satellite services also suffer from transmission delays due to bottlenecks in downloading data to ground stations. Through its space network, the SGIIN could overcome data silos between different space systems to improve battlefield data sharing and compress the military decision cycle. Ground-based information ports commissioned by the CETC could consolidate data from the land, sea, space, and air domains to enhance joint operations and enhance space situational awareness.
Additionally, the capabilities of the Tianxiang satellites suggest that future LEO satellites in the SGIIN Space Access Network would also carry payloads with applications such as navigation enhancements and remote sensing. The testing of multiple capabilities on satellites aligns with China’s stated goal of “one star, many uses” in its national civil space infrastructure development plan, and indicates that China’s future space capabilities could be significantly improved. To this end, Professor Yin Hao suggested that the SGIIN should be “intelligent” and “distributed”, in which the space network would include various types of satellite systems, including reconnaissance and surveillance satellites, early warning satellites, communication satellites, positioning and navigation satellites and meteorological satellites in all orbits, capable of processing and transmitting all types of satellite data.
Overall, the SGIIN project is still at an early stage of development and lags behind similar systems developed in the West. Much work is still needed to overcome technological challenges in the space segment, such as linking heterogeneous networks, reducing the latency of inter-satellite links and satellite-ground links, and securing satellite nodes and transmission links.
That said, since the launch of the SGIIN project, its national strategic importance has not diminished but has gained in urgency. The inclusion of 5G mobile technology and satellite internet in China’s “new infrastructure”, the prioritization of aerospace technology in the 14th Five-Year Plan, and China’s view of 6G mobile communications as an integration of terrestrial networks , air, and space signals a further acceleration of SGIIN’s development efforts.
In the future, the SGIIN concept could evolve to integrate LEO satellite constellations under development by public (e.g. Guowang, Hongyun, Hongyan) and private (e.g. Galaxy Space) companies, and enhance ISR, navigation and China’s early warning system in space.