BeiDou
The BeiDou Navigation Satellite System is a satellite-based radio navigation system owned and operated by the China National Space Administration. It provides geolocation and time information to a BDS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more BDS satellites. It does not require the user to transmit any data and operates independently of any telephonic or Internet reception, though these technologies can enhance the usefulness of the BDS positioning information.
The current service, BeiDou-3, provides full global coverage for timing and navigation, along with Russia's GLONASS, the European Galileo, and the US's GPS. It comprises satellites in three types of orbits: 24 in medium Earth orbit, 3 in inclined geosynchronous orbit, and 3 in geostationary orbit. The BeiDou-3 system was fully operational in July 2020. In 2016, BeiDou-3 reached millimeter-level accuracy with post-processing from a nationwide reference station network.
Predecessors included BeiDou-1, consisting of three satellites in a regional satellite navigation system. Since 2000, the system has mainly provided navigation services within China. In December 2012, as the design life of BeiDou-1 expired, it stopped operating.
The BeiDou-2 system was also a regional satellite navigation system containing 16 satellites, including 6 geostationary satellites, 6 inclined geosynchronous orbit satellites, and 4 medium earth orbit satellites. In November 2012, BeiDou-2 began to provide users with regional positioning services in the Asia-Pacific region. Within the region, BeiDou is more accurate than GPS.
In 2015, fifteen years after the satellite system was launched, it was generating a turnover of $31.5 billion per annum for major companies such as China Aerospace Science and Industry Corporation, AutoNavi, and Norinco. The industry has grown an average of over 20% in value annually to reach $64 billion in 2020.
In 2023, the International Civil Aviation Organization recognized the BeiDou system as a global standard for commercial aviation.
Nomenclature
The official English name of the system is BeiDou Navigation Satellite System. It is named after the Big Dipper asterism, which is known in Chinese as s=. The name literally means "Northern Dipper", the name given by ancient Chinese astronomers to the seven brightest stars of the Ursa Major constellation. Historically, this set of stars was used in navigation to locate the North Star. As such, the name BeiDou also serves as a metaphor for the purpose of the satellite navigation system.History
Conception and initial development
The original idea of a Chinese satellite navigation system was conceived by Chen Fangyun and his colleagues in the 1980s. The Gulf War in 1991 showcased how the GPS gave the US complete advantage on the battlefield and how satellite navigation systems can be used to conduct "space warfare". In 1993, China realised the risk of denied access to GPS during the Yinhe incident and including an alleged case in 1996 during the Third Taiwan Strait Crisis, gave impetus to the creation of its own indigenous satellite navigation system which officially began in 1994.According to the China National Space Administration, in 2010, the development of the system would be carried out in three steps:
- 2000–2003: experimental BeiDou navigation system consisting of three satellites
- By 2012: regional BeiDou navigation system covering China and neighboring regions
- By 2020: global BeiDou navigation system
On 2 November 2006, China announced that from 2008 BeiDou would offer an open service with an accuracy of 10 metres, timing of 0.2 microseconds, and speed of 0.2 metres/second.
In February 2007, the fourth and last satellite of the BeiDou-1 system, BeiDou-1D, was launched. It was reported that the satellite had suffered from a control system malfunction but was then fully restored.
In April 2007, the first satellite of BeiDou-2, namely Compass-M1 was successfully put into its working orbit. The second BeiDou-2 constellation satellite Compass-G2 was launched on 15 April 2009.
On 15 January 2010, the official website of the BeiDou Navigation Satellite System went online, and the system's third satellite was carried into its orbit by a Long March 3C rocket on 17 January 2010.
On 2 June 2010, the fourth satellite was launched successfully into orbit.
The fifth orbiter was launched into space from Xichang Satellite Launch Center by an LM-3I carrier rocket on 1 August 2010.
Three months later, on 1 November 2010, the sixth satellite was sent into orbit by LM-3C.
Another satellite, the BeiDou-2/Compass IGSO-5 satellite, was launched from the Xichang Satellite Launch Center by a Long March 3A on 1 December 2011.
Chinese involvement in Galileo system
In September 2003, China intended to join the European Galileo positioning system project and was to invest €230 million in Galileo over the next few years. At the time, it was believed that China's "BeiDou" navigation system would then only be used by its armed forces.In October 2004, China officially joined the Galileo project by signing the Agreement on the Cooperation in the Galileo Program between the "Galileo Joint Undertaking" and the "National Remote Sensing Centre of China" . Based on the Sino-European Cooperation Agreement on Galileo program, China Galileo Industries, the prime contractor of China's involvement in Galileo programs, was founded in December 2004. By April 2006, eleven cooperation projects within the Galileo framework had been signed between China and the EU.
Phase III
- In November 2014, BeiDou became part of the World-Wide Radionavigation System at the 94th meeting of the International Maritime Organization Maritime Safety Committee, which approved the "Navigation Safety Circular" of the BeiDou Navigation Satellite System.
- At Beijing time 21:52, 30 March 2015, the first new-generation BeiDou Navigation satellite was successfully set to orbit by a Long March 3C rocket.
- On 20 April 2019, a BeiDou satellite was successfully launched. Launch occurred at 22:41 Beijing time, and the Long March 3B delivered the BeiDou navigation payload into an elliptical transfer orbit ranging between 220 kilometres and 35,787 kilometres, with an inclination of 28.5° to the equator, according to U.S. military tracking data.
- On 23 June 2020, the final BeiDou satellite was successfully launched, the launch of the 55th satellite in the BeiDou family. The third iteration of the BeiDou Navigation Satellite System provides global coverage for timing and navigation, offering an alternative to Russia's GLONASS and the European Galileo positioning system, as well as the US's GPS.
Use outside China
Use in smartphones
Chinese smartphone maker Xiaomi featured BeiDou as early as August 2014, on their Mi 4. The earliest known smartphone by South-Korean smartphone maker Samsung to feature BeiDou is the Samsung Galaxy Note 4, released in October 2014. At a similar time, Japanese phone maker Sony implemented BeiDou for the first time on their Xperia Z3. The earliest BeiDou-capable smartphone by American smartphone maker Apple is the iPhone 13, released in September 2021.GPS vs. BeiDou Capabilities
The National Space-Based Positioning, Navigation, and Timing Advisory Board, which offers independent guidance to the U.S. government on GPS policy, issued a summary report from its 27th meeting held on 16–17 November 2022. During the meeting, it was highlighted that "GPS’s capabilities are now substantially inferior to those of China’s BeiDou."BeiDou-3
The third phase of the BeiDou system includes three GEO satellites, three IGSO satellites, and twenty-four MEO satellites which introduce new signal frequencies B1C/B1I/B1A, B2a/B2b, B3I/B3Q/B3A, and Bs test frequency. Interface control documents on the new open signals were published in 2017–2018.On 23 June 2020, the BDS-3 constellation deployment was fully completed after the last satellite was successfully launched at the Xichang Satellite Launch Center. BDS-3 satellites also include SBAS, Precise Point Positioning, and search and rescue transponder capabilities.
| BeiDou signal | B1I | B1Q | B1C | B1A | B2I | B2Q | B2a | B2b | B3I | B3Q | B3A |
| GIOVE/Compass signal | E2-I | E2-Q | E1-I | E1-Q | E5B-I | E5B-Q | E5a | E5b | E6-I | E6-Q | – |
| Access type | Open | Authorized | Open | Authorized | Open | Authorized | Open | Open | Open | Authorized | Authorized |
| Code modulation | BPSK | BPSK | MBOC | BOC | BPSK | BPSK | AltBOC | AltBOC | BPSK | BPSK | BOC |
| Carrier frequency | 1561.098 | 1561.098 | 1575.42 | 1575.42 | 1207.14 | 1207.14 | 1176.45 | 1207.14 | 1268.52 | 1268.52 | 1268.52 |
| Chip rate | 2.046 | 2.046 | 2.046 | 10.230 | 10.230 | 10.230 | |||||
| Code period | 2046 | 2046 | ?? | 10230 | |||||||
| Code period | 1.0 | >400 | 1.0 | >160 | 1.0 | >160 | |||||
| Symbols rate | 50 | 50 | 50 | ||||||||
| Navigation frames | 6 | 6 | |||||||||
| Navigation sub-frames | 30 | 30 | |||||||||
| Navigation period | 12.0 | 12.0 |
Characteristics of the "I" signals on E2 and E5B are generally similar to the civilian codes of GPS, but Compass signals have somewhat greater power. The notation of Compass signals used in this page follows the naming of the frequency bands and agrees with the notation used in the American literature on the subject, but the notation used by the Chinese seems to be different.
There has also been an experimental S band broadcast called "Bs" at 2492.028 MHz, following similar experiments on BeiDou-1.
As of early 2022, China had 49 operational positioning, navigation, and timing satellites to provide coverage through the Beidou system.