By Changfeng Yang,
Chief Architect of BeiDou Navigation Satellite System
As one of the four major GNSS providers, the establishment of BeiDou Navigation Satellite System (BDS) has been steadily developed, following a three-step strategy. By around 2020, BDS will form a nominal space constellation consisting of 30 satellites, including three satellites in geostationary Earth orbit (GEO), three satellites in inclined geosynchronous satellite orbit (IGSO) and 24 satellites in medium Earth orbit (MEO). It will provide global users with open and high-quality services free of charge, including navigation, positioning, timing, short message communication, search and rescue and so on.
BDS is aimed at developing into a world-class global navigation satellite system, with innovative and advanced technologies, extraordinary user experience, international development and worldwide presence, which can provide fundamental time and space reference for national defense and economic-social development, and advance the progress of high-tech and IT industries.
BDS has initiated several innovative attempts in the fields of both international satellite navigation and domestic aerospace for the first time, and paved a unique development path of a satellite navigation system, with an eye on the state conditions and distinctive features. On Jan. 9, 2017, the BD-2 Project won the top National Scientific and Technological Progress Award. In 2017, BDS achieved fruitful results in the aspects of system construction, integrated applications and international development.
System Construction
Through upgrading and reconstructing the ground system, the service performance, stability and availability of the BD-2 constellation have been improved. To achieve user-oriented services, the updated Interface Control Document (ICD) for B1C and B2a open service signals (Version 2.1) was released in accordance with the constellation change.
The international GNSS Monitoring and Assessment System (iGMAS) has been built, consisting of eight domestic monitoring stations and 16 overseas stations, to monitor and assess the service performances of BDS, GPS, GLONASS and Galileo at real-time worldwide. It has taken all factors into consideration, including constellation status, signal-in-space, navigation message, service performance and high-precision products, and so on. According to its analysis results, the nominal positioning accuracy of the BD-2 system in the coverage area has been optimized from 10 meters to 8 meters.
Development of the BD-3 System. On Nov. 5, the first pair of the 24 BD-3 MEO satellites were successfully launched, while another pair is planned to be launched by the end of the year.
The BD-3 satellites are equipped with B1C and B2a signals with optimized performance, which are compatible and interoperable with other GNSS signals. The interface control document of B1C and B2a signals (beta version) was released in September. The BD-3 satellites also adopt the higher-performance rubidium atomic clock with stability of E-14 and hydrogen atomic clock with stability of E-15. By utilizing new technologies, the signal-in-space (SIS) accuracy will be superior to 0.5 m; the position accuracy will be doubled or quadrupled, and reach 2.5 m to 5 m.
The BD-3 system will retain the short message communication service of its predecessors, and further enhance basic positioning, navigation and timing (PNT) service capabilities. Satellite-based augmentation system (SBAS) and search-and-rescue (SAR) services will be added and developed according to international standards.
After in-orbit tests and networking validation, the BD-3 satellites will be able to provide operational services, and accelerate the global coverage of BDS.
Ground-Based Augmentation. The Phase I construction of the BDS/GNSS ground-based augmentation system has been completed, consisting of 150 framework reference stations, 1,200 reference stations of higher density network, national data processing center, six industrial data-processing centers, and manufacturing of user terminals. This system has achieved basic service capabilities, and its service performance standard (version 1.0) has been released. Through integration with the internet, a cloud platform has been established to provide high-precision space-time information services, including real-time navigation services at meter-level and decimeter-level, as well as precise positioning services at centimeter-level and millimeter-level.
Satellite-Based Augmentation. Based on the International Civil Aviation Organization (ICAO) standards, system demonstration and validation work on the BeiDou Satellite-Based Augmentation System (BDSBAS) has been completed, and the technical status of the system has been confirmed in accordance of the next-generation SBAS Dual Frequency Multiple Constellation (DFMC) standards.
Integrated Applications
Currently, a great number of independent, self-controlled intellectual property rights on the fundamental BDS products have been achieved. World-class, advanced technologies have been developed. With the release of the first Chinese in-house developed meter-level fast positioning BDS chip, BDS applications have begun to embrace the era of meter-level positioning.
In 2017, the sales volume of BDS navigation chips and modules exceeded 50 million pieces, and that of high-precision surveying boards and navigation antenna captured 30% and 90% of market shares respectively. There are more than 14,000 enterprises (including more than 50 publicly listed companies), and more than 450,000 employees in China engaging in BDS-related business.
The annual output value of the publicly listed company in 2017 is more than RMB 50 billion (US $7.53 billion). The number of terminals produced by domestic enterprises surpasses 40 million pieces/sets. BDS has gained recognition from mainstream chip producers such as Qualcomm, Trimble, Hemisphere GNSS, Huawei, Samsung, u-blox, MTK, Broadcom, NovAtel and more, and the total number of terminals is estimated to surpass 300 million pieces or sets.
BDS continues to: - promote integrated applications and development of related industries;
- bring GNSS high-precision services in combination with cloud computing, Internet of Things, big data and other technologies;
- push forward the integration between BDS-related industries and high-end manufacturing, software, and integrated data industries.
BDS has been applied in the transportation, logistics, emergency rescue, marine fishing and other fields, which has greatly improved production efficiency, reduced resource consumption, and lowered pollution. For example, benefiting from the BDS applications in traffic management industry, the number of major accidents has decreased by 46.7%, and the death toll has been reduced by 48.9%. With BDS-based maritime applications, more than 10,000 lives have been saved.
BDS/GNSS augmentation services have been applied to precision agriculture, land mapping, monitoring on deformation and displacement of large-scale public facilities, and earthquake and geological hazard measurement and survey; the latter has provided important monitoring for public safety. As a result, the production of precision agriculture has increased by 5%, and the oil consumption by agricultural machinery has decreased by 10%. The time for surveying and mapping of national land is shortened from a few days to several seconds.
BDS has been fully put into mass applications. BDS-based navigation services have been adopted by various enterprises, such as Huawei, ZTE, Baidu, Autonavi, Alibaba, JD and others in the fields of manufacturing of mobile and smart terminals, location-based services (LBS), e-commerce, and so on. BDS-based LBS have been widely applied in the mass consumption sector and people’s livelihood, and many innovative applications have emerged, such as caring for seniors and children, shared vehicles, BDS-based logistics, and so on, which have been changing people’s lives and providing more convenience for the public.
International Development
At present, BDS has covered more than 50 countries and more than 3 billion people. BDS-related products have gained access to the markets of more than 70 countries and regions, more than 30 of which are along the (land-based) Belt and (maritime) Road (in line with the Belt and Road Initiative). Through joint applications with other compatible navigation satellite systems, BDS provides global users with diversified choices for better application experience.
Meanwhile, the iGMAS has contributed to the implementation of the Asia-Pacific Space Cooperation Organization project, iGMAS-International GNSS Service Pilot experimental project, and Sino-Russian monitoring and assessment cooperation, and has provided GNSS users with authentic third-party assessment results. China continuously pushes forward BDS to be recognized by the ICAO, International Maritime Organization (IMO), mobile communication standard Partnership Project and other organizations, to serve the world in line with international conventions.
In October, three PRN codes which are essential to the development of BDSBAS were assigned; the SBAS service provider identifier and UTC standard identifier have been assigned to BDSBAS by ICAO, which marks BDSBAS an official SBAS provider in the ICAO family, and lays the foundation for the follow-up construction of BDSBAS, as well as its provision of standard navigation services for the civil aviation sector.
In March, a multi-system (including GPS, BDS and GLONASS) ship-borne receiver standard was approved by the IMO. BDS has also been included in the PNT guidelines of maritime applications.
In the field of mobile communication, 26 technical standards that support the BDS positioning function have been adopted by the third- and fourth-generation mobile communication standard Partnership Projects.
Future Plans
BDS will keep improving its continuous stability and service accuracy. Two more BD-2 replacement satellites will be launched in 2018, ensuring its regional service performance will be remain stable and be enhanced.
Eighteen BD-3 MEO satellites and one BD-3 GEO satellite will be launched by around the end of 2018. Upon the deployment of those 19 satellites, BD-3 will possess the initial operational capability and serve the countries along the Belt and Road. The official version of ICD for B1C and B2a open service signals, as well as other system documents, will be released, in line with the operational status of BD-3 satellites, for the convenience of public applications.
In regard to augmentation systems, China plans to complete the construction of Phase II BDS/GNSS ground-based augmentation system in 2018, and advance the recognition of BDS-based high-precision services as public goods. In 2018, the first BDSBAS GEO satellite with the BDSBAS payload will be launched to start the deployment of the BDSBAS system.
In terms of applications and international development, China will give full play to the role of BDS in the integration procedure between industrialization and IT applications, to promote the development of information industry, adjustment and upgrading of industrial structure.
China will also strengthen the cooperation and communication with other navigation satellite system providers, carry out coordination under the framework of international organizations and multilateral platforms, improve the international development of BDS, provide better services for users along the Belt and Road, and expand BDS services to serve users worldwide.
