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China successfully sends final satellite of BeiDou system into space


Alwihda Info | Par peoplesdaily - 26 Juin 2020

As the BDS system continues to develop, the Long March-3A rocket series have also started to use three-mode receptors which are compatible with the BDS, GPS and GLONASS networks, Jiang Jie, chief engineer of the rocket series, with the China Academy of Launch Vehicle, also under the CASC, told the Global Times.


By Deng Xiaoci

China launched the last satellite of the BeiDou Navigation Satellite System on a Long March-3B rocket from the Xichang Satellite Launch Center in Sichuan at 9:43 am on June 23. Photo by Li Jieyi/People’s Daily Online
China launched the last satellite of the BeiDou Navigation Satellite System on a Long March-3B rocket from the Xichang Satellite Launch Center in Sichuan at 9:43 am on June 23. Photo by Li Jieyi/People’s Daily Online
“Ten, nine, eight…three, two, one. Launch,” the calm voice of 01 Commander Yin Xiangyuan in the valley of Liangshan mountain in Southwest China’s Sichuan Province, was soon overwhelmed by the thunderous boom of the rocket taking off on Tuesday.

Carrying the last satellite of China’s domestically developed BeiDou Navigation Satellite System, or BDS, the Long March-3B launch vehicle blasted off from the Xichang Satellite Launch Center on Tuesday morning.

And after a flight of around 30 minutes, the spacecraft, the third geostationary Earth orbit (GEO) satellite and 30th of the third-generation series of the BeiDou system, or BDS-3, successfully entered its planned orbit, marking the completion of the global geolocation network, which is also China’s largest space-based system and one of the four global navigation networks, along with the US’ GPS, Russia’s GLONASS and the European Galileo.

The launch of the final satellite of China’s indigenous BeiDou system had been previously scheduled on June 16, but was delayed after technical problems were found with the Long March-3B rocket in pre-launch tests.

Space launches have always been full of challenges and sometimes faced with high risks of failure. The postponement of the final BeiDou launch and resumption after resolving the problems once again demonstrated that Chinese space scientists uphold the scientific spirit, allowing zero errors at any stage of the mission, insiders said.

World-class performance

The latest GEO satellite is the 55th BDS system, and will work with other members of the network, allowing global users to access high-accuracy navigation, positioning and timing as well as communication services.

Compared to previous generation series, the constellation of BDS-3 with an array of 30 satellites flying on three different orbit planes – three at the GEO, three at the inclined geosynchronous orbits, and 24 at the medium Earth orbit, have higher bandwidth, enabling enhanced communication capability and carrying more accurate and stable atomic clocks to improve the precision of timing and navigation services, according to the project contractor China Academy of Space Technology under the state owned space giant China Aerospace Science and Technology Corporation (CASC).

The BDS-3 also possesses better messaging capability, increasing its unique short message service capacity from 120 Chinese characters to 1,200 per message, and the higher communication bandwidth also expands the user capacity from 500,000 to 5 million users.

BDS-3 is also capable of providing precise point positioning service (PPP) with a decimeter-level dynamic accuracy and centimeter-level static accuracy, meaning it can support applications such as auto-pilot for vehicles and precision docking of ships.

Yang Changfeng, the chief architect of the BDS, told the Global Times on Monday that China’s BDS is compatible with the US’ GPS, Russia’s GLONASS and Europe’s Galileo, and users worldwide can freely choose any four satellites with the best signals from the global navigation satellite systems with over 100 satellites.

According to the chief architect, the BDS has satellites on three orbit planes in the Asia-Pacific region, which makes it more capable of resisting disturbances from occlusion even in such environments with multi-layer surfaces in the urban areas as well as in forests.

Users in low latitude areas in the Asia-Pacific region can enjoy non-stop navigation services from the BDS in these circumstances, and the accuracy of the BDS service is just as good as that of the US' GPS, and of world-class quality globally, Yang noted.

According to the China Satellite Navigation Office on Tuesday, the majority of the world have started using the BDS.

Hardwork of generations

China began research and development into the country's indigenous satellite system in 1994, aiming to reduce its reliance on foreign networks, especially under the complicated external environment.

The first BeiDou satellite entered orbit in 2,000, and started providing positioning, navigation, timing and messaging services to domestic users in China and users in the Asia-Pacific region in December 2012.

The BDS system started providing global services at the end of 2018, when construction of the BDS-3 primary system had been completed.

BeiDou has been supporting dozens of businesses and public sectors in China, ranging from transportation and agriculture to electric power transmission and fisheries, and tens of millions of BeiDou-enabled terminal devices have been sold and are in use.

In the field of transportation, BDS has been widely used in the monitoring and management of priority transportation, highway infrastructure safety, port scheduling, and real-time high-precision positioning.

By the end of 2019, more than 6.5 million road operating vehicles, 40,000 postal and express delivery vehicles, 80,000 buses in 36 central cities, 3,200 inland navigation facilities, and 2,900 marine navigation facilities have adopted BDS, forming the world’s largest dynamic monitoring system for road operating vehicles.

More than 70,000 fisheries and law-enforcement vessels have installed BeiDou terminals and more than 10,000 people have been rescued thanks to the BeiDou application.

Time reference for public security networks has been synchronized based on the BDS timing services. BDS has played an important role in ensuring security at major events, such as the Asia-Pacific Economic Cooperation (APEC) Meeting and the G20 Summit.

In the field of smart phones, mainstream chip manufacturers both at home and abroad have introduced integrated chips that are compatible with BDS. By the third quarter of 2019, more than 400 smartphone models sold in China supported positioning functions, of which about 300 models supported BDS.

The scale of navigation satellite positioning and navigation industry in China has reached 345 billion yuan ($48.6 billion) by 2019, up 14.4 percent from the previous year, according to an annual industry report.

Cao Chong, a Beijing-based senior expert on satellite navigation industry, told the Global Times the industry scale is expected to exceed 400 billion by the end of 2020.

Cao said the next step to further promote the BDS system in market both at home and abroad lies in the research and development of terminal capabilities, which should keep up with the enhanced power of BDS-3. “There are huge market potentials to be released.”

The Tuesday mission marked the 44th BeiDou satellite-launching flight for the Long March-3A rocket series since October 31, 2000, which the Long March-3B rocket belongs to. The rockets have sent 59 BeiDou satellites, including four experimental ones, into orbit, with a 100 percent success rate.

As the BDS system continues to develop, the Long March-3A rocket series have also started to use three-mode receptors which are compatible with the BDS, GPS and GLONASS networks, Jiang Jie, chief engineer of the rocket series, with the China Academy of Launch Vehicle, also under the CASC, told the Global Times.

As the three modes all complement each other, they work together to improve the orbiting accuracy of rockets and reduce consumption of propellants, Jiang noted.

Source: Global Times