Tag: International GNSS Monitoring and Assessment System

  • Directions 2023: BDS Development Continues Apace

    Directions 2023: BDS Development Continues Apace

    In 2022, the BeiDou Navigation Satellite System (BDS) continued to improve its service performance, expand global applications, and deepen and promote international cooperation.

    On Nov. 4, 2022, a white paper titled “China’s BeiDou Navigation Satellite System in the New Era” was published. The paper shows the continuous, stable and reliable operational capability of BDS, its applications achievements across the industries, international development with openness and integration, and unremitting pursuit of helping to build a community with a shared future for humanity and a better world.

    System Services Performances

    In orbit are 45 BDS operational satellites, including 15 BDS-2 satellites and 30 BDS-3 satellites. Figure 1 shows the number of visible BDS satellites worldwide as of BDT 06:00 on Dec. 6, 2022.

    Picture1.Directions2023
    Figure 1. Number of visible BDS satellites. (Image: www.csno-tarc.cn)

    BDS has reached a continuity of 99.996% and an availability of 99%. The innovative constellation involves inter-satellite links, signal system optimization, intelligent operation and maintenance, software reconstruction and upgrading of in-orbit satellites, and global test and assessment.
    As measured by the International GNSS Monitoring and Assessment System (iGMAS), the BDS global positioning accuracy is less than 1.5 m horizontally and 2.5 m vertically (95% confidence) — better than the nominal service performance parameters.

    So far, the measured signal power spectrum envelope of the BDS satellites remains consistent with the superior signal quality; the signal-in-space accuracy of any BDS satellite is better than 4.6 m. The time offset between BDT and UTC (NTSC) remains within 26 ns.

    The BDS Coordination Framework has maintained consistency with the International Terrestrial Reference Frame 2014, and the accuracy is better than 3 cm. The orbital accuracy of the broadcast ephemeris of the BDS-3 medium Earth orbit (MEO) satellite is better than 0.5 m, and the clock offset of the broadcast ephemeris of the BDS-3 satellites is better than 5 ns.

    BDS concentrates on construction of the application infrastructure and has established four major characteristic service platforms:

    • Short Message Communication Service
    • Satellite-based Augmentation System Service
    • Search-and-Rescue Service
    • Ground Based Augmentation System Service.

    These platforms will expand and upgrade the applications and provide more efficient and convenient services for users.

    The BDS Short Message Communication Service platform realizes the interconnection with ground mobile communication systems and networks, and integrates the BDS short message communication functionality into smartphones without the need to change the SIM card or contact number.

    For the BDS Satellite-based Augmentation System Service platform, the system’s ground segment includes 30 monitoring stations and two data processing centers. The system will provide single frequency (SF) and dual-frequency multi-constellation (DFMC) services through GEO satellites. The Civil Aviation Administration of China has initiated and organized the technical testing and certification of SF service before applications.

    The BDS Search-and-Rescue Service provides users with distress alert information access and distribution, as well as return link services. It is currently at the initial operational stage with sound performances. The operational status of the BDS SAR payload has been submitted to Cospas-Sarsat.

    The BDS Ground-Based Augmentation System Service platform’s real-time positioning accuracy can reach 2 cm horizontally and 5 cm vertically. The post-processing accuracy can reach 2 mm horizontally and 5 mm vertically. At present, the BDS ground-based augmentation network has provided the A-BDS positioning and the BDS high-precision services for more than 1.5 billion users in more than 230 countries and regions, with services delivered 2 trillion times in total, equivalent to nearly 3 billion on average per day. BDS has provided high-precision positioning services for more than 20 million mobile phones in the country.

    The BDS Applications Industry

    The BDS applications industry has achieved sustainable development. In 2021, the total output of China’s satellite navigation and location-based service industry reached about 469 billion yuan (about 67.4 billion U.S. dollars), with a compound annual growth rate of more than 20%. A complete industrial chain covering chips, modules, antennas, boards, terminals and services has been established.

    Industrial applications. BDS has been fully applied in various industries — including transportation, agriculture, forestry and fishery, public security, disaster mitigation and relief — and has been integrated into infrastructure such as electric power, water conservation, finance and communications.

    As BDS applications fields expand, its in-depth applications have been growing as well. As of June 2022, more than 8 million BDS terminals had been installed in the transportation sector. More than 1.3 million terminals were used in the farming, forestry, livestock and fishing industries, and more than 1.8 million terminals were adopted by public security agencies. Large-scale BDS applications have been advanced in communication and timing services, meteorological monitoring, emergency response and disaster mitigation, and urban management. In emerging applications sectors, BDS has served epidemic prevention and control, telemedicine, caring for seniors, promoting the realization of intelligent health services that serve everyone, and accelerating intelligence and modernization in related fields.

    Mass market applications. BDS has been widely used in mass market applications, such as mobile phones and wearable devices. In the first half of 2022, among all types of smartphones that applied for network access in China, 128 supported the BDS-based positioning function. More than 130 million smartphones supporting BDS services were shipped, accounting for more than 98% of the country’s total volume. The BDS positioning service is used more than 100 billion times daily on average for a platform that supports mobile map navigation. In particular, mobile phones have been fitted with high-precision positioning services. Lane-level navigation has been implemented in eight cities in China, including Shenzhen, Chongqing and Tianjin. The first mobile phone in the world that supports BDS-3 regional short message communication services has been officially released, enabling users to send short messages through BDS.

    BDS international applications. BDS has been applied in more than half the countries and regions in the world, with more diversified application modes and application fields.

    BDS products, technologies and services have been recognized by more international users:

    • In Mozambique, BDS-based UAVs have greatly improved the efficiency of plant protection operations
    • In Lebanon, BDS-based high-precision technology has been successfully applied to the construction and measurement of the port of Beirut
    • In Burkina Faso, BDS supported surveying and mapping during the construction of hospitals to prevent and control local infectious diseases, such as COVID-19
    • In Saudi Arabia, BDS is widely used in fields such as surveying and the collection of geographic information, the construction of urban and municipal infrastructure, and the positioning of personnel or vehicles in deserts
    • In Asia, BDS-based high-precision positioning services are contributing to the monitoring of Sarez Lake Dam in Tajikistan, the completion of the China-Kyrgyzstan-Uzbekistan Highway, the China-Kazakhstan crude oil pipeline, and the routine operation of China-Europe Railway Express.

    International Cooperation

    Following the principles of openness, cooperation and resource sharing, BDS has been actively carrying out practical international cooperation and exchanges as well as facilitating the development of global satellite navigation.

    Multilateral cooperation. BDS representatives continue to participate in international activities under the framework of the United Nations International Committee on GNSS and other multilateral forums, to advocate joint development of global satellite navigation by contributing Chinese wisdom and proposals. BDS has also participated in international academic conferences in the field of satellite navigation, such as the Institute of Navigation meetings, the Munich Satellite Navigation Summit, and the Multi-GNSS Asia Conference.

    Bilateral cooperation. The Ninth Meeting of the China-Russia Project Committee on Major Strategic Cooperation in Satellite Navigation was successfully held in September 2022. Under the framework of the Committee, BDS and GLONASS have carried out continuous cooperation in such areas as compatibility and interoperability, system performance testing and assessment, and joint applications. China’s Satellite Navigation Office signed cooperation documents in the field of satellite navigation with partners from the United Arab Emirates and the Arab Civil Aviation Organization, to carry out extensive cooperation and continue to deepen cooperation with Pakistan, Iraq, Thailand, Argentina, South Africa and other countries.

    International Standards. BDS is increasingly recognized by international organizations such as the International Maritime Organization (IMO), the International Civil Aviation Organization (ICAO), Cospas-Sarsat, IEC, 3GPP and RTCM. In November 2022, the BDS Message Service System (BDMSS) was ratified by the Global Maritime Distress and Safety System (GMDSS), making BDMSS the third GMDSS satellite communication system recognized by the IMO. The Declaration of Intent for Cospas-Sarsat MEOSAR Cooperation was signed between the cooperating agencies (from Canada, France, Russia, and the United States) of the International Cospas-Sarsat Program and the Maritime Safety Administration of China, meaning China formally becomes the provider of the Cospas-Sarsat space segment.

    The Future

    In the future, BDS will launch back-up satellites to ensure better performance by upgrading the constellation’s availability. While maintaining stable operation, BDS will speed up in combination with new technologies such as 5G, artificial intelligence and Big Data to build a more ubiquitous, more integrated, and more intelligent national comprehensive PNT system by 2035. BDS will continuously adhere to the development concept that “BDS is developed by China, dedicated to the world and aiming to be world class,” promote system development and make contributions to social development and construction of the community with a shared future for mankind.


    For analogous updates on the other three GNSS constellations, please see:

  • Directions 2022: BDS enters new era of global services

    Directions 2022: BDS enters new era of global services

    Yang Changfeng is BeiDou’s Chief Architect. (Photo: BeiDou Navigation Satellite System)
    Yang Changfeng is BeiDou’s Chief Architect. (Photo: BeiDou Navigation Satellite System)

    Construction of the BeiDou Navigation Satellite System (BDS-3) has been completed. The system was formally commissioned on July 31, 2020. In 2021, BDS continued to improve performance, expand applications and deepen cooperation, and has achieved sustained, stable and rapid development.

    System Performance and Services

    Currently, 45 BDS satellites are operational in orbit — 15 BDS-2 satellites and 30 BDS-3 satellites jointly provide seven types of services to users. Specifically, for the entire planet, the system provides three services:

    • Positioning, navigation and timing (PNT).
    • Global short-message communication.
    • International search-and-rescue (SAR) services.

    For the Asia-Pacific region, the system provides four additional services:

    • Satellite-based augmentation.
    • Ground-based augmentation.
    • Precise point positioning.
    • Regional short-message communication services.

    The system has been operating continuously and stably since commissioning, with the average value of satellite availability better than 0.99 and the average value of satellite continuity better than 0.999.

    PNT Service. As actually measured by the International GNSS Monitoring and Assessment System (iGMAS), the global horizontal positioning accuracy is about 1.52 meters, the vertical positioning accuracy is about 2.64 meters (B1C signal single frequency, 95% confidence), the velocity measurement accuracy is better than 0.1 m/s, and timing accuracy is better than 20 nanoseconds. The performance is better in the Asia-Pacific region.

    FIGURE 1 shows the number of visible BDS satellites worldwide at BDT 00:00 on Nov. 18, 2021. Among them, the number of visible BDS satellites exceeds 20 in some areas of the Asia-Pacific region.

    figure 1. Number of visible BDS satellites, elevation ≥5° (2021/11/18/00:00 BDT). (CREDIT: www.csno-tarc.cn)
    Figure 1. Number of visible BDS satellites, elevation ≥5° (2021/11/18/00:00 BDT). (CREDIT: www.csno-tarc.cn)

    Global Short Message Communication Service. Trial service is provided through 14 medium-Earth-orbit (MEO) satellites for authorized users and low-orbit satellites, with a maximum single-message length of 560 bits, equivalent to about 40 Chinese characters.

    Search-and-Rescue Service. A COSPAS/SARSAT-compliant MEOSAR service is provided by six payloads deployed on six MEO satellites. A B2b signal-based Return Link Service (RLS) is provided through 24 MEO and three IGSO satellites, which have completed testing and verification and are in the process of coordination within the framework of COSPAS-SARSAT.

    Satellite-Based Augmentation Service. China’s Civil Aviation Administration is organizing satellite-ground integrated test and evaluation, and the positioning accuracy, alarm time, integrity risk and other indicators meet the requirements.

    Ground-Based Augmentation Service. Real-time centimeter-level and post-processing millimeter-level services are provided for industrial and public users, based on the regional network reference stations built in China.

    Precise Point Positioning Service. PPP signals are broadcast by three GEO satellites. The measured horizontal positioning accuracy is 0.24 m, the vertical positioning accuracy is 0.41 m (95% confidence), and the convergence time is less than 20 minutes.

    Regional Short Message Communication Service. The short-message communication function has been tested and verified for integration into public mobile phones; large-scale application is planned.

    Development of the Applications Industry

    Large-scale applications of BDS have entered a critical stage of liberalization, industrialization and internationalization. The overall output value of China’s satellite navigation and location-based service industry continued to grow in 2020, up to 403.3 billion yuan (US$63.2 billion), which is about 16.9% more than its value in 2019. In terms of BDS-3-enabled basic products, an industrial chain is gradually maturing, comprised of BDS/GNSS basic chips, modules, boards, antennas and other components.

    The certification and testing system of basic BDS products has been established and implemented. BDS is already supported by most mainstream chips. BDS is increasingly being integrated into the daily life of the general public. It is becoming the standard configuration for positioning functions of smartphones and other mass-market products.

    Smartphone manufacturers such as Xiaomi, Huawei, Apple and Samsung already support BDS. In the first three quarters of 2021, among all types of smartphones applying for online access in China, 72.3% supported positioning function based on BDS, accounting for 93.5% of the total sales volume. The BDS ground-based augmentation function has been introduced into smartphones to achieve high-precision positioning at the 1-meter level; lane-level navigation is being piloted in several cities in China.

    In terms of industrial applications, BDS has fully served multiple industries including transportation, public security, disaster relief, agriculture, forestry, animal husbandry and fishing. It has accelerated the integration into electricity, finance, communications and other infrastructure. In particular, in the fight against COVID-19 through scientific and technological approaches, BDS-based precise positioning has facilitated the efficient supply and circulation of anti-epidemic materials.

    BDS-based solutions for land rights determination, precision agriculture and smart ports have served the economic and social development of countries in Asia, Eastern Europe and Africa, and BDS-based products have been applied in more than half of the world’s countries and regions.

    International Cooperation

    BDS has always adhered to the development concepts of openness, cooperation and resource sharing; actively carried out practical international exchanges and cooperation; and contributed to China’s peaceful use of outer space.

    Bilaterally, the Eighth Meeting of the China-Russia Project Committee on Major Strategic Cooperation in Satellite Navigation was held in October 2021. Both sides jointly formulated and signed the Roadmap for Cooperation in the Field of Satellite Navigation from 2021 to 2025, providing planning and guidance for China-Russia satellite navigation cooperation in the next five years. Also, China’s Satellite Navigation Office signed a memorandum of understanding on satellite navigation cooperation with the National Committee on Space Activities of the Republic of Argentina and the South African National Space Agency, and formally established a regular cooperation mechanism.

    BDS is gradually being integrated into international standards, and is steadily promoting ratification by international standards bodies, including in the civil aviation, maritime, SAR, mobile communications and electrotechnical fields. Several international standards supporting BDS have been released. The Chinese government has drafted a letter of commitment to the International Civil Aviation Organization (ICAO), stating that BDS will provide basic services free of charge to civil aviation users around the world. The International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA) has officially issued a standard that ratifies BDSBAS, so that global marine users can carry out applications based on it. The Third Generation Partnership Project has started the standardization of BDS-3’s B2a and B3I signals. In the detection standard for Indicating Radio Beacon Locator of the Global Maritime Distress and Safety System issued by the International Electrotechnical Commission, BDS receivers and BDS-based SAR services will be supported.

    The Chinese government is steadily advancing the rule of law, attaching great importance to and comprehensively promoting the rule of law for satellite navigation. A legal system on BDS has been formed, consisting of national policies, industrial and local policies and regulations, and more. The legislative process of the Satellite Navigation Regulations of the People’s Republic of China has been actively promoted to ensure the healthy, rapid and sustainable development of the satellite industry. In May 2021, China issued a development report on the rule of law of BDS.

    Follow-Up Plan

    In the future, on the one hand BDS will ensure stable operation, while on the other hand it will focus on the development of backup satellites, and complete the production, state optimization and ground testing of backup satellites. Backup BDS-3 satellites with better performance will be launched as needed to further improve the reliability of the constellation. By adhering to the development concept of “BDS is developed by China, dedicated to the world and aiming to be first class,” carrying forward the BDS spirit of the new era of “independent innovation, open integration, unity of all, pursuit of excellence,” BDS will serve the world and benefit all humankind.

    • Number of BDS-3 satellites in orbit: 30
    • Signals broadcast: B1I, B3I, B1C, B2a, and B2b

    Yang Changfeng is chief architect of the BeiDou Navigation Satellite System and a Chinese Academy of Engineering academician.