Kai Lin Tay
The “Space-Ground Integrated Information Network” (tiandi yitihua xinxiwangluo, SGIIN) is a “mega engineering 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 to “promote the comprehensive integration of space-based 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 instance, developed similar networks such as the Global Information Grid and the Transformational Satellite Communications Systems in 2007 and 2008 respectively, which integrate space-based and terrestrial networks for military purposes. China’s development of these integrated networks appears to lag behind U.S. military programs even though it first raised the intent to develop a space-ground integrated network system in a 2000 white paper.
Nevertheless, given the important implications of the SGIIN project on China’s overall economic and military capabilities, it’s important to take stock of the project’s developments and achievements to date, especially following the recent conclusion of the 13th Five-Year Plan period.
Background and Concepts
The SGIIN project is led by the China Electronics Technology Corporation (CETC), a state-owned enterprise in the Fortune Global 500, which leads China’s cyber research, among many fields. In essence, the SGIIN is envisioned to be a unified system that interconnect space-based networks and ground-based networks to provide on-demand and secure network services for sea, land, air and space users globally.
Space-based networks typically comprise a space segment and a ground segment. The space segment of the SGIIN’s space-based networks consists of satellite nodes in Geostationary Earth Orbit (GEO) (less than 35,000 kilometers from Earth) and 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 intersatellite links.
The ground segment of space-based networks is made up of interconnected ground nodes, including gateway stations and information ports, which are linked to both satellite nodes (in space) and terrestrial networks (on Earth) (i.e. mobile communication networks, wireless internet). Crucially, the availability of space-based networks in the SGIIN circumvents the need for China to build an extensive network of ground stations globally, so only few locally-based ground stations would be required to establish global coverage.
Recent Developments
The CETC’s work on the SGIIN is founded upon strong collaboration with other local institutes. In January 2018, it established a joint laboratory with Tsinghua University to research key technologies; in May 2018, it founded a joint innovation center with Zhijiang Laboratory; in late 2018, it gathered a coalition of over 40 research institutes, universities, and industry players with information network and aerospace expertise to carry out top-level design, standard formulation, and technical research of the SGIIN.
CETC also leads the SGIIN Hefei Center, which houses the SGIIN (Anhui) research institute. Inaugurated in December 2018, the research institute is a collaborative innovation base focused on developing key technologies including LEO satellites, floating platform communications, space computing, and information integration in 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 space-based backbone satellite node.
CETC is also responsible for building the SGIIN ground information ports, tasked with the aggregation and processing of all types of remote sensing, weather, and navigation satellite data to provide information services for the government, public, and private businesses. In March 2019, the prototype system of the SGIIN ground information port was officially launched for an 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 unit model for the construction of the space-based access network. The two satellites successfully conducted various technology experiments for the first time, including space-based networking information transmission, intersatellite measurement, navigation enhancement, and space-based aviation and navigation surveillance.
Potential Military Implications
While the SGIIN ostensibly aims to serve national economic and social development purposes, China’s military-civil fusion strategy would most likely play out in the SGIIN. Professor Li Deren, a distinguished photogrammetry and remote sensing scientist, emphasized that building a space-based, real-time service system integrated with positioning, navigation, timing, remote sensing, and communication functions is crucial for both civilian and national security needs. Similarly, Professor Yin Hao, a communications expert and director at the People’s Liberation Army Academy of Military Science (Systems Engineering Department), advocated building an integrated system that provides satellite navigation and remote sensing services for both military and civilian use.
Regarding potential military implications, SGIIN would improve all-domain situational awareness by connecting terrestrial and non-terrestrial (airborne, space) 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 communications satellites are underutilized and have not been effectively leveraged for joint operations. Its satellites services also suffer from transmission delays arising from bottlenecks in downloading data to the ground stations. Through its space-based network, the SGIIN could overcome data stovepipes between different space systems to enhance battlefield data sharing and compress the military decision cycle. The ground information ports commissioned by the CETC could consolidate data from land, sea, space, and air domains to improve joint operations and enhance space situational awareness.
Additionally, the Tianxiang satellites’ capabilities portend that future LEO satellites in the SGIIN’s space-based access network would also carry payloads with applications such as navigation enhancements and remote sensing. The testing of multiple capabilities on the satellites aligns with China’s stated objective of “one star, many uses” in its national civilian space infrastructure development plan, and indicates that China’s future space-based capabilities could be greatly enhanced. To this end, Professor Yin Hao suggested that the SGIIN to be “intelligentized” and “distributed,” in which the space-based network would comprise of various types of satellite systems, including reconnaissance and surveillance satellites, early warning satellites, communications satellites, positioning and navigation satellites, and meteorological satellites in all orbits, with the capacity to process and transmit all types of satellite data.
Overall, the SGIIN project is still in an early stage of development and falls 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 intersatellite links and satellite-ground links and securing the satellites nodes and transmission links.
That said, since the SGIIN project was initiated, its national strategic importance has not waned but increased in urgency. The inclusion of 5G mobile technology and the satellite internet in China’s “new infrastructure,” the prioritization of aerospace technology in the 14th Five-Year Plan, and China’s vision of 6G mobile communications to be an integration of land, air, and space networks all point to a further acceleration in efforts to develop the SGIIN.
Looking ahead, the SGIIN concept may evolve to integrate developing LEO satellite constellations by state-owned (e.g. Guowang, Hongyun, Hongyan) and private firms (e.g. Galaxy Space), and boost China’s ISR, navigation, and early warning capabilities through space.
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