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2021/07/10
Yang Changfeng, Chief Architect, BeiDou Navigation Satellite System. (Photo: BeiDou)
By Yang Changfeng
Chief Architect,
BeiDou Navigation Satellite System
As one of the core Global Navigation Satellite Systems (GNSS) providers, the BeiDou Navigation Satellite System (“BDS”) has been developed steadily following a three-step strategy. BDS has been providing global services since the end of 2018. By around 2020, the BDS-3 system will be entirely completed to provide global users with free, open and high-quality navigation, positioning, timing, short message communication and other services. A more ubiquitous, integrated and intelligent positioning, navigation, timing system will be built before 2035.
In 2019, BDS has progressed with regard to aspects of system construction, integrated applications and international development.
System Construction
Accelerating Satellite Deployment. From January to November 2019, three BDS-3 satellites in inclined geosynchronous satellite orbit (IGSO) and four satellites in medium Earth orbit (MEO) were launched, and one IGSO satellite has completed in-orbit tests, to further improve the global system constellation.
The last two MEO satellites are planned to be launched by the end of 2019, marking the completion of the BDS core global constellation deployment. By June 2020, another two GEO satellites will be launched, and the full deployment of the BDS-3 system will be completed.
Ground System Construction. In 2019, 12 new ground operation and control stations (including one uplink station and 11 class-II monitoring stations) have been built, to complete the satellite-ground joint debug and integration tests, and the overall operation of the system is stable.
By the end of October 2019, 34 BDS satellites are operating in orbit to provide services to global users, including 15 BDS-2 satellites and 19 BDS-3 satellites.
Improving Service Performance
Key Service Areas. In May 2019, the last BDS-2 backup satellite was launched to further improve the performance in the key service areas of the BDS-2 system. As the BDS-3 satellites go into operation, the accuracy and availability of the BDS B1I and B3I signals, in the BDS-2service area, has been improved by about 30% and 5% respectively, compared with that of solely relying on the BDS-2 system.
Global Service Areas. The BDS B1I and B3I service areas have been expanded from the Asia Pacific region to the world, and the accuracy and availability have been further improved. With the condition of PDOP ≤6, the availability is better than 99% in most regions all over the world (in parts of the United States, better than 97%). In the global area, the mean value of the actual measured positioning accuracy is about 3.6m horizontally and 6.6m vertically, velocity measurement accuracy is about 0.05m/s, and timing accuracy is about 9.8 nanoseconds (95% confidence). So far, the BDS-3 new signals, B1C and B2a, have possessed service capacity worldwide. The system availability is better than 87%, in the condition of PDOP ≤ 6. The mean value of the actual measured positioning accuracy is about 2.4m horizontally and 4.3m vertically, velocity measurement accuracy is about 0.06m/s and timing accuracy is about 19.9 nanoseconds (95% confidence).
BDS Availability (PDOP≤6). (Image: BeiDou)
Measured BDS B1C Positioning Accuracy. (Image: BeiDou)
Building of the Featured Capacity. The BDS/GNSS ground based augmentation system has been providing basic services. It consists of 155 framework reference stations and nearly 2,200 regional stations in China. The system has carried out high-precision applications in many fields, such as surveying and mapping, land resources, earthquake, transportation and meteorology. Its basic services include real-time positioning at the meter, decimeter and centimeter level, as well as precise post-processing positioning at the millimeter level.
The BeiDou Satellite-Based Augmentation System (BDSBAS) is being developed in accordance with International Civil Aviation Organization (ICAO) standards to provide navigation services with superior accuracy and integrity. In 2019, the first GEO satellite with the BDSBAS payload has been tested in orbit and the satellite is in good condition.
Integrated Applications
As the system construction accelerates, BDS is also making great efforts to strengthen the development of the fundamental products and applications in various fields. The integrated applications adopt the “BDS+” model to stimulate the growth of satellite navigation industry.
Fundamental Products. At present, the fundamental BDS products have been used in such areas as mass market applications, of which the performance has reached or is close-to the world-class level. The development of full-frequency integrated high-precision chips is near its completion, and the performance of the BDS chips will improve further. By the end of 2019, BDS navigation chips, modules and antennas have been exported to more than 100 countries and regions. In 2018, the domestic output value was more than RMB 300 billion (US$43 billion), in which the BDS contribution exceeds 80%.
Industrial Applications. BDS has been widely used in various fields — communication and transportation, public security, agriculture, forestry, animal husbandry and fishery, hydrological monitoring, meteorological forecast, time synchronization, power dispatching, disaster prevention and mitigation — generating significant economic and social benefits. In the field of transportation, by September 2019, more than 6.47 million road operating vehicles and 42,300 postal and express delivery vehicles in China are using BDS, and the world’s largest dynamic supervision system of operating vehicles has been formed, which effectively improved management efficiency and road transportation safety.
In agriculture, a BDS-based automatic driving system has been equipped on more than 20,000 sets of agricultural machinery and equipment, saving 50% of the labor cost. The BDS-based agricultural machinery operation supervision platform and the IoT platform has been serving 10 million units of agricultural machinery equipment, greatly improving management and operational efficiency.
In disaster prevention and mitigation, a tri-level platform covering the national ministry, the provinces, and cities and counties has been built to offer six-tier application services, with more than 45,000 terminals using BDS. The BDS/GNSS high-precision technologies have been applied in the field of geological disaster monitoring, while the landslides in Gansu province have been successfully forecast repeatedly, with time accuracy at the second level and deformation accuracy at the millimeter level.
Mass Market Applications. The BDS-based navigation and positioning services have been adopted by various enterprises in the fields of e-commerce, smart mobile terminal manufacture, location-based services (LBS), the sharing economy and the mass market, thereby changing people’s production and life style profoundly. Mainstream manufacturers in China and around the world have introduced BDS-compatible chips that integrate communication and navigation functions.
According to Chinese market statistics, in the third quarter of 2019, 151 types of mobile phones applying for license have positioning functions, among which 110 models support BDS. Using BDS/GNSS ground based augmentation stations, the spatial-temporal services including centimeter-level positioning, millimeter-level perception and nanometer-level timing services can be provided, while the accelerated positioning services cover 220 countries and regions with more than 390 million global users.
International Development
Bilateral Cooperation. BDS continues to carry out bilateral cooperation with other navigation satellite systems, to promote compatibility and joint applications. China and the United States have set up joint working groups in areas such as compatibility and interoperability, augmentation systems and civil services to continuously develop cooperation and exchanges.
China and the EU set up a technical working group on the compatibility and interoperability between the BDS and Galileo systems to carry out coordination, exchanges and cooperation, under the framework of the China-EU space cooperation dialogue and the International Telecommunications Union (ITU). The agreement between the Government of the People’s Republic of China and the Government of the Russian Federation on Cooperation in the Field of the Use of BeiDou and GLONASS for Peaceful Purposes has come into effect.
In August 2019, China and the Russian Federation held their sixth bilateral meeting in Kazan, Russia, signed the site survey certificate of GNSS monitoring stations, and achieved many cooperation results. In addition, the bilateral cooperation with Iraq, Tunisia and Saudi Arabia has also been steadily promoted.
Multilateral Cooperation. During the 62nd session of the Committee on the Peaceful Uses of Outer Space (COPUOS) in June 2019, an exhibition on ancient Chinese navigation technologies was held at the Vienna International Center with the theme “From Compass to BeiDou,” which vividly demonstrated China’s brilliant achievements in timing, mapping, cartography and navigation science and technology. In April and October, 2019, the second China-Arab States BDS Cooperation Forum and China-Central Asia BDS cooperation forum were held in Tunis and Nanning, China, respectively, to promote the BDS to serve the Arab region and Central Asian countries.
The BDS Overseas Applications Were Steadily Promoted. With BDS high-precision products being exported, BDS has been widely used in different regions and fields, such as land registration, precision agriculture, warehouse logistics in ASEAN countries, construction in Western Asia, airport timing and piling at seas in South Asia, electric power inspection in Eastern Europe, and land survey in African countries. As BDS-3 system continues to improve construction, it will provide quality services for more people in a wider area.
Ratification of BDS by International Standards. BDS has made a clear schedule to be ratified by the ICAO standards in 2020. It has formulated 26 standards in the field of international mobile communication based on the BDS B1I signal, and other standards based on the B1C and B2a signals are being developed. A receiver positioning result output protocol (NMEA0183) and a receiver data exchange format (RINEX 3.04) supporting BDS are to be released. Technical parameters and index information of BDS search and rescue (SAR) payloads are included in relevant COSPAS-SARSAT documents, and the development and in-orbit test of the first batch of SAR payload has been completed. The first BDS standard in the International Electrotechnical Commission (IEC) has been developed and approved and is expected to be released in June 2020.
Future Plans
After BDS achieves global service capabilities by 2020, it will further improve global navigation, positioning, timing and regional short-message communication services, and finalize global short-message communication, international search and rescue, satellite-based augmentation, precise point positioning, and other service capabilities. China’s BDS will contribute Chinese solutions to the world, and give full play of its role, with a renewed attitude, stronger capabilities and better services, to serve the world and benefit humankind.
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