Engineering:BeiDou

From HandWiki
Short description: Chinese satellite navigation system
BeiDou Navigation Satellite System
Beidou logo.png

Country/ies of originChina
Operator(s)CNSA
TypeMilitary, commercial
StatusOperational
CoverageGlobal
Accuracy3.6 m (global, public)
2.6 m (Asia Pacific, public)
10 cm (encrypted)[1]
Constellation size
Total satellites35 (2020)
Satellites in orbit35
First launch31 October 2000
Last launch23 June 2020[2]
Total launches59[3]
Orbital characteristics
Regime(s)GEO, IGSO, MEO
Websiteen.beidou.gov.cn
Geodesy
Azimutalprojektion-schief kl-cropped.png
Fundamentals
Concepts
Technologies
Standards (history)
NGVD 29 Sea Level Datum 1929
OSGB36 Ordnance Survey Great Britain 1936
SK-42 Systema Koordinat 1942 goda
ED50 European Datum 1950
SAD69 South American Datum 1969
GRS 80 Geodetic Reference System 1980
ISO 6709 Geographic point coord. 1983
NAD 83 North American Datum 1983
WGS 84 World Geodetic System 1984
NAVD 88 N. American Vertical Datum 1988
ETRS89 European Terrestrial Ref. Sys. 1989
GCJ-02 Chinese obfuscated datum 2002
Geo URI Internet link to a point 2010

The BeiDou Navigation Satellite System (BDS; Chinese: 北斗卫星导航系统; pinyin: Běidǒu Wèixīng Dǎoháng Xìtǒng) is a Chinese satellite navigation system. It consists of two separate satellite constellations. The first BeiDou system, officially called the BeiDou Satellite Navigation Experimental System and also known as BeiDou-1, consisted of three satellites which, beginning in 2000, offered limited coverage and navigation services, mainly for users in China and neighboring regions. BeiDou-1 was decommissioned at the end of 2012. 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 for global coverage for timing and navigation, offering an alternative to Russia's GLONASS, the European Galileo positioning system, and the US's GPS.

The second generation of the system, officially called the BeiDou Navigation Satellite System (BDS) and also known as COMPASS or BeiDou-2, became operational in China in December 2011 with a partial constellation of 10 satellites in orbit.[4] Since December 2012, it has been offering services to customers in the Asia-Pacific region.[5]

In 2015, China launched the third generation BeiDou system (BeiDou-3) for global coverage. The first BDS-3 satellite was launched on 30 March 2015.[6] On 27 December 2018, BeiDou Navigation Satellite System started providing global services.[7][8] The 35th and the final satellite of BDS-3 was launched into orbit on 23 June 2020.[9] It was said in 2016 that BeiDou-3 will reach millimeter-level accuracy (with post-processing).[10]

According to China Daily, 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 Holdings Ltd., and China North Industries Group Corp.[11] The industry has grown an average of over 20% in value annually to reach $64 billion in 2020 according to Xinhua citing data.[12][13]

Domestic industry reports forecast the satellite navigation service market output value, directly generated and driven by the Beidou system, will be worth 1 trillion yuan ($156.22 billion) by 2025, and $467 billion by 2035.[14][15]

Nomenclature

The official English name of the system is BeiDou Navigation Satellite System.[16] It is named after the Big Dipper asterism, which is known in Chinese as Běidǒu (Chinese: 北斗). The name literally means "Northern Dipper", the name given by ancient Chinese astronomers to the seven brightest stars of the Ursa Major constellation.[17] 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.[citation needed]

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.[18] The risk of denied access to GPS, including an alleged case in 1996 during the Third Taiwan Strait Crisis, gave impetus to the creation of BeiDou.[19]

According to the China National Space Administration, in 2010, the development of the system would be carried out in three steps:[20]

  1. 2000–2003: experimental BeiDou navigation system consisting of three satellites
  2. By 2012: regional BeiDou navigation system covering China and neighboring regions
  3. By 2020: global BeiDou navigation system

The first satellite, BeiDou-1A, was launched on 30 October 2000, followed by BeiDou-1B on 20 December 2000. The third satellite, BeiDou-1C (a backup satellite), was put into orbit on 25 May 2003.[21][22] The successful launch of BeiDou-1C also meant the establishment of the BeiDou-1 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.[23]

In February 2007, the fourth and last satellite of the BeiDou-1 system, BeiDou-1D (sometimes called BeiDou-2A, serving as a backup satellite), was launched.[24] It was reported that the satellite had suffered from a control system malfunction but was then fully restored.[25][26]

In April 2007, the first satellite of BeiDou-2, namely Compass-M1 (to validate frequencies for the BeiDou-2 constellation) was successfully put into its working orbit. The second BeiDou-2 constellation satellite Compass-G2 was launched on 15 April 2009.[27]

On 15 January 2010, the official website of the BeiDou Navigation Satellite System went online,[28] and the system's third satellite (Compass-G1) was carried into its orbit by a Long March 3C rocket on 17 January 2010.[28]

On 2 June 2010, the fourth satellite was launched successfully into orbit.[29]

The fifth orbiter was launched into space from Xichang Satellite Launch Center by an LM-3I carrier rocket on 1 August 2010.[30]

Three months later, on 1 November 2010, the sixth satellite was sent into orbit by LM-3C.[31]

Another satellite, the Beidou-2/Compass IGSO-5 (fifth inclined geosynchronous orbit) satellite, was launched from the Xichang Satellite Launch Center by a Long March 3A on 1 December 2011 (UTC).[32]

Chinese involvement in Galileo system

In September 2003, China intended to join the European Galileo positioning system project and was to invest €230 million (US$296 million, £160 million) in Galileo over the next few years.[33] At the time, it was believed that China's "BeiDou" navigation system would then only be used by its armed forces.[23]

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" (GJU) and the "National Remote Sensing Centre of China" (NRSCC).[34] Based on the Sino-European Cooperation Agreement on Galileo program, China Galileo Industries (CGI),[35] the prime contractor of the China's involvement in Galileo programs, was founded in December 2004.[36] By April 2006, eleven cooperation projects within the Galileo framework had been signed between China and EU.[37]

However, the Hong Kong-based South China Morning Post reported in January 2008 that China was not satisfied with its role in the Galileo project and was to compete with Galileo in the Asian market.[citation needed]

Phase III

  • In November 2014, Beidou became part of the World-Wide Radionavigation System (WWRNS) at the 94th meeting of the International Maritime Organization (IMO) Maritime Safety Committee,[38] which approved the "Navigation Safety Circular" of the BeiDou Navigation Satellite System (BDS).[39][40]
  • At Beijing time 21:52, 30 March 2015, the first new-generation BeiDou Navigation satellite (and the 17th overall) was successfully set to orbit by a Long March 3C rocket.[41][42]
  • 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.[43]
  • 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 promises to provide 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.[44]

BeiDou-1

Description

Coverage polygon of BeiDou-1

BeiDou-1 was an experimental regional navigation system, which consisted of four satellites (three working satellites and one backup satellite). The satellites themselves were based on the Chinese DFH-3 geostationary communications satellite and had a launch weight of 1000 kg each.[45]

Unlike the American GPS, Russian GLONASS, and European Galileo systems, which use medium Earth orbit satellites, BeiDou-1 used satellites in geostationary orbit. This means that the system does not require a large constellation of satellites, but it also limits the coverage to areas on Earth where the satellites are visible.[21] The area that can be serviced is from longitude 70° E to 140° E and from latitude 5° N to 55° N. A frequency of the system is 2491.75 MHz.[25]

Completion

The first satellite, BeiDou-1A, was launched on 31 October 2000. The second satellite, BeiDou-1B, was successfully launched on 21 December 2000. The last operational satellite of the constellation, BeiDou-1C, was launched on 25 May 2003.[21]

Position calculation

In 2007, the official Xinhua News Agency reported that the resolution of the BeiDou system was as low as 0.5 metre.[46] With the existing user terminals it appears that the calibrated accuracy is 20 m (100 m, uncalibrated).[47]

Terminals

In 2008, a BeiDou-1 ground terminal cost around CN¥ 20,000 (US$2,929), almost 10 times the price of a contemporary GPS terminal.[48] The price of the terminals was explained as being due to the cost of imported microchips.[49] At the China High-Tech Fair ELEXCON of November 2009 in Shenzhen, a BeiDou terminal priced at CN¥ 3,000 was presented.[50]

Applications

  • Over 1000 BeiDou-1 terminals were used after the 2008 Sichuan earthquake, providing information from the disaster area.[51]
  • As of October 2009, all Chinese border guards in Yunnan were equipped with BeiDou-1 devices.[52]

Sun Jiadong, the chief designer of the navigation system, said in 2010 that "Many organizations have been using our system for a while, and they like it very much".[53]

Decommissioning

BeiDou-1 was decommissioned at the end of 2012, after the BeiDou-2 system became operational.

BeiDou-2

Description

Coverage polygon of BeiDou-2 in 2012
Frequency allocation of GPS, Galileo, and COMPASS; the light red color of E1 band indicates that the transmission in this band has not yet been detected.

BeiDou-2 (formerly known as COMPASS)[54] is not an extension to the older BeiDou-1, but rather supersedes it outright. The new system is a constellation of 35 satellites, which include 5 geostationary orbit satellites for backward compatibility with BeiDou-1, and 30 non-geostationary satellites (27 in medium Earth orbit and 3 in inclined geosynchronous orbit),[55] that offer complete coverage of the globe.

The ranging signals are based on the CDMA principle and have complex structure typical of Galileo or modernized GPS. Similar to the other global navigation satellite systems (GNSSs), there are two levels of positioning service: open (public) and restricted (military). The public service is available globally to general users. When all the currently planned GNSSs are deployed, users of multi-constellation receivers will benefit from a total over 100 satellites, which will significantly improve all aspects of positioning, especially availability of the signals in so-called urban canyons.[56] The general designer of the COMPASS navigation system is Sun Jiadong, who is also the general designer of its predecessor, the original BeiDou navigation system.[citation needed] All BeiDou satellites are equipped with laser retroreflector arrays for satellite laser ranging[57] and the verification of the orbit quality.[58][59]

Accuracy

There are two levels of service provided – a free service to civilians and licensed service to the Chinese government and military.[29][60][61] The free civilian service has a 10-metre location-tracking accuracy, synchronizes clocks with an accuracy of 10 nanoseconds, and measures speeds to within 0.2 m/s. The restricted military service has a location accuracy of 10 centimetre,[62] can be used for communication, and will supply information about the system status to the user.[citation needed] In 2019, the International GNSS Service started providing precise orbits of BeiDou satellites in experimental products.[57]

To date, the military service has been granted only to the People's Liberation Army and to the Pakistan Armed Forces.[63][64][65]

Frequencies

Frequencies for COMPASS are allocated in four bands: E1, E2, E5B, and E6; they overlap with Galileo. The fact of overlapping could be convenient from the point of view of the receiver design, but on the other hand raises the issues of system interference, especially within E1 and E2 bands, which are allocated for Galileo's publicly regulated service.[66] However, under International Telecommunication Union (ITU) policies, the first nation to start broadcasting in a specific frequency will have priority to that frequency, and any subsequent users will be required to obtain permission prior to using that frequency, and otherwise ensure that their broadcasts do not interfere with the original nation's broadcasts. As of 2009, it appeared that Chinese COMPASS satellites would start transmitting in the E1, E2, E5B, and E6 bands before Europe's Galileo satellites and thus have primary rights to these frequency ranges.[67]

Although little was officially announced by Chinese authorities about the signals of the new system, the launch of the first COMPASS satellite permitted independent researchers not only to study general characteristics of the signals, but even to build a COMPASS receiver.[citation needed]

Compass-M1

Compass-M1 is an experimental satellite launched for signal testing and validation and for the frequency filing on 14 April 2007. The role of Compass-M1 for Compass is similar to the role of the GIOVE satellites for the Galileo system. The orbit of Compass-M1 is nearly circular, has an altitude of 21,150 km and an inclination of 55.5°.[citation needed]

Compass-M1 transmits in 3 bands: E2, E5B, and E6. In each frequency band two coherent sub-signals have been detected with a phase shift of 90° (in quadrature). These signal components are further referred to as "I" and "Q". The "I" components have shorter codes and are likely to be intended for the open service. The "Q" components have much longer codes, are more interference resistive, and are probably intended for the restricted service.[citation needed]

The investigation of the transmitted signals started immediately after the launch of Compass-M1 on 14 April 2007. Soon after in June 2007, engineers at CNES reported the spectrum and structure of the signals.[68] A month later, researchers from Stanford University reported the complete decoding of the "I" signals components.[69][70] The knowledge of the codes allowed a group of engineers at Septentrio to build the COMPASS receiver[71] and report tracking and multipath characteristics of the "I" signals on E2 and E5B.[72]

Operation

Ground track of BeiDou-M5 (2012-050A)

In December 2011, the system went into operation on a trial basis.[73] It has started providing navigation, positioning and timing data to China and the neighbouring area for free from 27 December 2011. During this trial run, Compass will offer positioning accuracy to within 25 metre, but the precision will improve as more satellites are launched. Upon the system's official launch, it pledged to offer general users positioning information accurate to the nearest 10 m, measure speeds within 0.2 metre per second, and provide signals for clock synchronisation accurate to 0.02 microseconds.[74]

The BeiDou-2 system began offering services for the Asia-Pacific region in December 2012.[5] At this time, the system could provide positioning data between longitude 55° E to 180° E and from latitude 55° S to 55° N.[75]

The new-generation BeiDou satellites support short message service.[42]

Completion

In December 2011, Xinhua stated that "[t]he basic structure of the BeiDou system has now been established, and engineers are now conducting comprehensive system test and evaluation. The system will provide test-run services of positioning, navigation and time for China and the neighboring areas before the end of this year, according to the authorities".[76] The system became operational in the China region that same month.[4] The global navigation system should be finished by 2020.[77]

As of December 2012, 16 satellites for BeiDou-2 had been launched, with 14 in service. And as of December 2017, 150 m Chinese smartphones (20% of the market) were equipped to utilize Beidou.[78]

BeiDou-3

The third phase of the BeiDou system (BDS-3) includes three GEO satellites, three IGSO satellites, and twenty-four MEO satellites which introduce new signal frequencies B1C/B1I/B1A (1575.42 MHz), B2a/B2b (1191.795 MHz), B3I/B3Q/B3A (1268.52 MHz), and Bs test frequency (2492.028 MHz). Interface control documents on the new open signals were published in 2017–2018.[79]

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.[80][81] BDS-3 satellites also include SBAS (B1C, B2a, B1A) and search and rescue transponder capabilities.[82]

Characteristics of BeiDou-2/Compass and BeiDou-3 signals[83][79]
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(2) BPSK(2) MBOC(6,1,1/11) BOC(14,2) BPSK(2) BPSK(10) AltBOC(15,10) AltBOC(15,10) BPSK(10) BPSK(10) BOC(15,2.5)
Carrier frequency (MHz) 1561.098 1561.098 1575.42 1575.42 1207.14 1207.14 1176.45 1207.14 1268.52 1268.52 1268.52
Chip rate (Mchips/s) 2.046 2.046 2.046 10.230 10.230 10.230
Code period (chips) 2046 ? 2046 ?? 10230 ?
Code period (ms) 1.0 >400 1.0 >160 1.0 >160
Symbols rate (bits/s) 50 ? 50 ? 50 ?
Navigation frames (s) 6 ? 6 ? ? ?
Navigation sub-frames (s) 30 ? 30 ? ? ?
Navigation period (min) 12.0 ? 12.0 ? ? ?

Characteristics of the "I" signals on E2 and E5B are generally similar to the civilian codes of GPS (L1-CA and L2C), 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.[citation needed]

There has also been an experimental S band broadcast called "Bs" at 2492.028 MHz,[79] following similar experiments on Beidou-1.[84]

Constellation

Summary of satellites, as of 23 June 2020
Block Launch
period 		Satellite launches Currently in orbit
and healthy
Success Failure Planned
1 2000–2006 4 0 0 0
2 2007–2019 20 0 0 12
3 2015–present 35 0 0 30
Total 59 0 0 42

The regional BeiDou-1 system was decommissioned at the end of 2012.[citation needed]

The first satellite of the second-generation system, Compass-M1 was launched in 2007. It was followed by further nine satellites during 2009–2011, achieving functional regional coverage. A total of 16 satellites were launched during this phase.[citation needed]

In 2015, the system began its transition towards global coverage with the first launch of a new-generation of satellites,[42] and the 17th one within the new system. On 25 July 2015, the 18th and 19th satellites were successfully launched from the Xichang Satellite Launch Center, marking the first time for China to launch two satellites at once on top of a Long March 3B/Expedition 1 carrier rocket. The Expedition-1 is an independent upper stage capable of delivering one or more spacecraft into different orbits. On 29 September 2015, the 20th satellite was launched, carrying a hydrogen maser for the first time within the system.[85]

In 2016, the 21st, 22nd and 23rd satellites were launched from Xichang Satellite Launch Center,[86] the last two of which entered into service on 5 August 2016 and 30 November 2016, respectively.[87][88]

Animation of BeiDou-3
Around the Earth
Around the Earth – polar view
Earth fixed frame – equatorial view, front
Earth fixed frame – equatorial view, side
   Earth ·    I1  ·    I2  ·    I3 ·    G1 ·    G2 ·    G3

See also

References

  1. ↑ May 27, Merryl Azriel on; Space, 2013 in; Relations, International (27 May 2013). "US Department of Defense Reports on China's Space Capabilities". http://www.spacesafetymagazine.com/space-on-earth/international-relations/department-defense-reports-chinas-space-capabilities/. 
  2. ↑ "China puts final satellite for Beidou network into orbit -state media". Financialpost (Financial Post). https://business.financialpost.com/pmn/business-pmn/china-puts-final-satellite-for-beidou-network-into-orbit-state-media. 
  3. ↑ "北斗卫星发射一览表". http://www.beidou.gov.cn/xt/fsgl/. 
  4. ↑ 4.0 4.1 "China GPS rival Beidou starts offering navigation data". BBC. 27 December 2011. https://www.bbc.co.uk/news/technology-16337648. 
  5. ↑ 5.0 5.1 "China's Beidou GPS-substitute opens to public in Asia". BBC. 27 December 2012. https://www.bbc.co.uk/news/technology-20852150. 
  6. ↑ "中国北斗导航卫星再次进入密集发射期". 中国新闻社. 31 March 2015. http://www.chinanews.com/gn/2015/03-31/7170977.shtml. 
  7. ↑ PTI, K. J. M. Varma (27 December 2018). "China's BeiDou navigation satellite, rival to US GPS, starts global services". https://www.livemint.com/Technology/9rkTgLBMCHVottY3rP636J/Chinas-BeiDou-navigation-satellite-rival-to-US-GPS-starts.html. 
  8. ↑ "The BDS-3 Preliminary System Is Completed to Provide Global Services". http://en.beidou.gov.cn/WHATSNEWS/201812/t20181227_16837.html. 
  9. ↑ "China puts final satellite for Beidou network into orbit – state media" (in en). Reuters. 23 June 2020. https://uk.reuters.com/article/us-space-exploration-china-satellite/china-puts-final-satellite-for-beidou-network-into-orbit-state-media-idUKKBN23U08P. 
  10. ↑ "Directions 2017: BeiDou's road to global service". GPS World. 6 December 2016. http://gpsworld.com/directions-2017-beidous-road-to-global-service/. 
  11. ↑ "Sky's the limit for Beidou's clients[1- Chinadaily.com.cn"]. http://www.chinadaily.com.cn/bizchina/tech/2015-11/16/content_22464083.htm. 
  12. ↑ "China's answer to GPS poised to create US$156 billion industry" (in en). 2021-05-27. https://www.scmp.com/tech/tech-war/article/3135055/us-china-tech-war-chinas-gps-rival-beidou-poised-support-industry. 
  13. ↑ "China's Beidou navigation system to serve $156 billion home market by 2025" (in en). Reuters. 2021-05-26. https://www.reuters.com/article/ctech-us-space-exploration-china-beidou-idCAKCN2D70FR-OCATC. 
  14. ↑ GNSS, Inside (2021-05-26). "BeiDou Headed Upwards of 1 Trillion this Decade. That's Yuan." (in en-US). https://insidegnss.com/beidou-headed-upwards-of-1-trillion-this-decade-thats-yuan/. 
  15. ↑ "The Application of China's Beidou System reached a market size of $62.7 Billion in 2020" (in en-AU). https://au.lifestyle.yahoo.com/application-chinas-beidou-system-reached-090000733.html. 
  16. ↑ "English Name of BeiDou". http://www.beidou.gov.cn/2013/03/29/20130329622a1d8c79ee4e5d849867358c1a97bf.html. 
  17. ↑ Atkins, William (5 February 2007). "Chinese BeiDou navigation satellite launched from Long March 3A rocket". iTWire.com. http://www.itwire.com/science-news/space/9201-chinese-BeiDou-navigation-satellite-launched-from-long-march-3a-rocket. 
  18. ↑ "̽北斗记 ——探秘中国北斗卫星导航定位系统". http://focus.news.163.com/10/1231/09/6P7JHOMM00011SM9.html. 
  19. ↑ "'Unforgettable humiliation' led to development of GPS equivalent". https://www.scmp.com/article/698161/unforgettable-humiliation-led-development-gps-equivalent. 
  20. ↑ "The construction of BeiDou navigation system steps into important stage, "Three Steps" development guideline clear and certain" (in zh). China National Space Administration. 19 May 2010. http://www.BeiDou.gov.cn/2010/05/19/20100519101180c595f14a6d9938a42a2d796b56.html. 
  21. ↑ 21.0 21.1 21.2 "Comparable with American and Russian in terms of performance, BeiDou-1 navigates for China" (in zh). China National Space Administration. 30 May 2003. http://www.cnsa.gov.cn/n615708/n620172/n677078/n751578/62676.html. 
  22. ↑ Pike, John. "BeiDou (Big Dipper)". Space. GlobalSecurity.org. http://www.globalsecurity.org/space/world/china/BeiDou.htm. 
  23. ↑ 23.0 23.1 Marks, Paul (8 November 2006). "China's satellite navigation plans threaten Galileo". New Scientist. https://www.newscientist.com/article/dn10472-chinas-satellite-navigation-plans-threaten-galileo.html. 
  24. ↑ "China puts new navigation satellite into orbit". Gov.cn. 3 February 2007. http://english.gov.cn/2007-02/03/content_516638.htm. 
  25. ↑ 25.0 25.1 "BeiDou 1 Experimental Satellite Navigation System". SinoDefence.com. 24 September 2008. http://www.sinodefence.com/space/spacecraft/beidou1.asp. 
  26. ↑ "60-day works in space – Story of reparation of the BeiDou satellite" (in zh). Sohu. 18 April 2007. http://news.sohu.com/20070418/n249522961.shtml. 
  27. ↑ "Compass due Next Year". Magazine article. Asian Surveying and Mapping. 4 May 2009. http://www.asmmag.com/news/compass-due-next-year. 
  28. ↑ 28.0 28.1 "China successfully launched the third BeiDou satellite" (in zh). Sohu. 17 January 2010. http://news.sohu.com/20100117/n269631862.shtml. 
  29. ↑ 29.0 29.1 "China sends Beidou navigation satellite to orbit". Spaceflight Now. 2 June 2010. http://www.spaceflightnow.com/news/n1006/02longmarch/. 
  30. ↑ "China successfully launches fifth satellite for its own global navigation network". Xinhua. 1 August 2010. http://news.xinhuanet.com/english2010/china/2010-08/01/c_13424634.htm. 
  31. ↑ "China launches 6th satellite for indigenous global navigation, positioning network". gov.cn. 1 November 2010. http://english.gov.cn/2010-11/01/content_1735077.htm. 
  32. ↑ "Beidou Launch Completes Regional Nav System". GPS World. 6 December 2010. http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regional-nav-system-12375/. 
  33. ↑ "China joins EU's satellite network". Business News (BBC News). 19 September 2003. http://news.bbc.co.uk/1/hi/business/3121682.stm. 
  34. ↑ "First contracts of the Galileo project signed, China is to invest 200 million Euro" (in zh). Xinhua. 29 July 2005. http://news.xinhuanet.com/newscenter/2005-07/29/content_3281533.htm. 
  35. ↑ China Galileo Industries (CGI)
  36. ↑ "About us". China Galileo Industries. http://www.chinagi.com.cn/yw/gsjjxx.asp. 
  37. ↑ "Eleven projects within the China-EU Galileo project have been signed and are carrying out" (in zh). Xinhua. 13 April 2006. http://news3.xinhuanet.com/politics/2006-04/13/content_4420183.htm. 
  38. ↑ "SOLAS amendments to make IGF Code mandatory approved by Maritime Safety Committee". Maritime Safety Committee (MSC), 94th session, 17–21 November 2014 (International Maritime Organization). 26 November 2014. http://www.imo.org/MediaCentre/PressBriefings/Pages/40-MSC94wrap.aspx. 
  39. ↑ Feng, Bruce (4 December 2014). "A Step Forward for Beidou, China's Satellite Navigation System". The New York Times. http://sinosphere.blogs.nytimes.com/2014/12/04/a-step-forward-for-beidou-chinas-satellite-navigation-system/. 
  40. ↑ "Chinese Beidou Navigation Satellite System officially into Global Radio Navigation System". BeiDou. 1 December 2014. http://www.beidou.gov.cn/2014/12/01/2014120161d5b9e6272547ddb9d141b4129491f4.html. 
  41. ↑ Barbosa, Rui C. (30 March 2015). "Long March 3C in secretive launch with new Upper Stage". NASASpaceFlight.com. http://www.nasaspaceflight.com/2015/03/long-march-3c-launch-new-upper-stage/. 
  42. ↑ 42.0 42.1 42.2 "China successfully launched the first New-Generation Beidou Navigation Satellite". BeiDou. 1 April 2015. http://www.beidou.gov.cn/2015/04/01/20150401b4b91ddc213a45129a665ea3272b5aed.html. 
  43. ↑ Clark, Stephen. "Beidou navigation satellite successfully launched by China – Spaceflight Now". https://spaceflightnow.com/2019/04/22/beidou-navigation-satellite-successfully-launched-by-china/. 
  44. ↑ "China launches final satellite in GPS-like Beidou system". phys.org. https://phys.org/news/2020-06-china-satellite-gps-like-beidou.html. 
  45. ↑ Goebel, Greg (1 September 2008). "International Navigation Satellite Systems". vectorsite.net. http://www.vectorsite.net/ttgps_2.html#m3. 
  46. ↑ "BeiDou navigation system first goes to public, with resolution 0.5 metre" (in zh). Phoenix Television. 18 July 2007. http://orig.news.ifeng.com/mil/2/200707/0718_340_158622.shtml. 
  47. ↑ "BeiDou Products". BDStar Navigation. http://www.navchina.com/english/productlist.asp?classid=12. 
  48. ↑ "BeiDou-1 commercial controversy: 10 times the price of GPS terminal" (in zh). NetEase. 28 June 2008. http://tech.163.com/08/0628/08/4FGTUVT9000915BE.html. 
  49. ↑ "Why is China's Beidou terminal so expensive?". PRLog. 31 August 2008. http://www.prlog.org/10112053-why-is-chinas-beidou-terminal-so-expensive.html. 
  50. ↑ "3000Yuan BeiDou Satellite Positioning System terminal solution was presented at ELEXCON" (in zh). eetrend.com. 17 November 2009. http://www.eetrend.com/news/100022852. 
  51. ↑ "Hongkong report: BeiDou-1 played an important role in rescuing, 7 nations providing free satellite data" (in zh). Sohu. 20 May 2008. http://news.sohu.com/20080520/n256965516.shtml. 
  52. ↑ "BeiDou-1 has equipped Yunnan troops, leading to command reform" (in zh). Sohu. 14 October 2009. http://news.sohu.com/20091014/n267346694.shtml. 
  53. ↑ "China To Set Up Independent Satellite Navigation System". SpaceDaily.com. 24 May 2010. http://www.spacedaily.com/reports/China_To_Set_Up_Independent_Satellite_Navigation_System_999.html. 
  54. ↑ "The Logo Image of BeiDou Navigation Satellite System Issued". BeiDou.gov.cn. 27 December 2012. http://www.beidou.gov.cn/2012/12/27/20121227db0e01c98b044232875e2f85cf5bb2a3.html. 
  55. ↑ "China Launches Another Compass GEO Navigation Satellite". Inside GNSS. 2 June 2010. http://www.insidegnss.com/node/2134. Retrieved 4 June 2010. 
  56. ↑ G. Gibbons. China GNSS 101. Compass in the rearview mirror. Inside GNSS, January/February 2008, pp. 62–63 [1]
  57. ↑ 57.0 57.1 Sośnica, Krzysztof; Zajdel, Radosław; Bury, Grzegorz; Bosy, Jarosław; Moore, Michael; Masoumi, Salim (2020). "Quality assessment of experimental IGS multi-GNSS combined orbits". GPS Solutions 24 (54). doi:10.1007/s10291-020-0965-5. 
  58. ↑ Bury, Grzegorz; Sośnica, Krzysztof; Zajdel, Radosław (2019). "Multi-GNSS orbit determination using satellite laser ranging". Journal of Geodesy 93 (12): 2447–2463. doi:10.1007/s00190-018-1143-1. Bibcode: 2019JGeod..93.2447B. 
  59. ↑ Kazmierski, Kamil; Zajdel, Radoslaw; Sośnica, Krzysztof (2020). "Evolution of orbit and clock quality for real-time multi-GNSS solutions". GPS Solutions 24 (111). doi:10.1007/s10291-020-01026-6. 
  60. ↑ "Introduction of the BeiDou Navigation Satellite System" (in zh). BeiDou.gov.cn. 15 January 2010. http://www.beidou.gov.cn/2010/03/06/20100306e4ed1ecefebb41fa933ceee48024aa00.html. 
  61. ↑ Dotson, John (15 July 2020). "The Beidou Satellite Network and the "Space Silk Road" in Eurasia" (in en-US). https://jamestown.org/program/the-beidou-satellite-network-and-the-space-silk-road-in-eurasia/. 
  62. ↑ "Precise orbit determination of Beidou Satellites with precise positioning". Science China. 2012. http://earth.scichina.com:8080/sciDe/EN/abstract/abstract507876.shtml. 
  63. ↑ "GPS rival Beidou will cover Asia Pac by end of the year". The Register. 17 May 2012. https://www.theregister.co.uk/2012/05/17/beidou_ready_2012_three_satellites/. 
  64. ↑ "US Department of Defense Reports on China's Space Capabilities". Space Safety Magazine. 27 May 2013. http://www.spacesafetymagazine.com/tag/beidou/. 
  65. ↑ "China will make BeiDou Navigation Satellite System available to global users by 2020". Next Big Future. 28 June 2016. http://www.nextbigfuture.com/2016/06/china-will-make-beidou-navigation.html. 
  66. ↑ Galileo, Compass on collision course, GPS World, April 2008, p. 27
  67. ↑ Levin, Dan (23 March 2009). "Chinese square off with Europe in space". The New York Times. China. https://www.nytimes.com/2009/03/23/technology/23iht-galileo23.html?_r=1&scp=1&sq=chinese%20europe%20galileo&st=cse. 
  68. ↑ T. Grelier, J. Dantepal, A. Delatour, A. Ghion, L. Ries, Initial observation and analysis of Compass MEO satellite signals, Inside GNSS, May/June 2007 [2]
  69. ↑ G. Xingxin Gao, A. Chen, S. Lo, D. De Lorenzo, P. Enge, GNSS over China. The Compass MEO satellite codes. Inside GNSS, July/August 2007, pp. 36–43 [3]
  70. ↑ G. Xingxin Gao, A. Chen, Sh. Lo, D. De Lorenzo and Per Enge, Compass-M1 broadcast codes and their application to acquisition and tracking, Proceedings of the ION National Technical Meeting 2008, San Diego, California, January 2008."Compass-M1 Broadcast Codes and Their Application to Acquisition and Tracking". http://www.stanford.edu/~gracegao/publications/ION_NTM_08%20Compass.pdf. 
  71. ↑ W. De Wilde, F. Boon, J.-M. Sleewaegen, F. Wilms, More Compass points. Tracking China’s MEO satellite on a hardware receiver. Inside GNSS, July/August 2007, pp. 44–48. [4]
  72. ↑ A. Simsky, D. Mertens, Wim De Wilde, Field Experience with Compass-M1 E2 and E5B Signals. Proceedings of ENC GNSS 2008, Toulouse, 22–25 April 2008.
  73. ↑ "Satellite navigation system launched". China Daily. 28 December 2010. http://europe.chinadaily.com.cn/business/2011-12/28/content_14343656.htm. 
  74. ↑ "China GPS rival Beidou starts offering navigation data". BBC. 27 December 2010. https://www.bbc.co.uk/news/technology-16337648. 
  75. ↑ "Error: no |title= specified when using {{Cite web}}" (in zh). WWW.BEIDOU.GOV.CN. 26 December 2012. http://www.beidou.gov.cn/2012/12/26/20121226bac9c0de3e6b430d997368b19ff2c6b5.html. 
  76. ↑ "China launches 10th satellite for independent navigation system". Xinhua. 2 December 2011. http://news.xinhuanet.com/english2010/sci/2011-12/02/c_131283096.htm. 
  77. ↑ "BeiDou navigation system covers Asia-Pacific region till 2012" (in zh). Xinhua News Agency. 3 March 2010. http://news.xinhuanet.com/mil/2010-03/03/content_13087844.htm. 
  78. ↑ "A digital Silk Road". http://www.theworldin.com/article/14433/edition2018digital-silk-road. 
  79. ↑ 79.0 79.1 79.2 Update on the BeiDou Satellite Navigation System . 12th ICG Meeting. Jia-Qing Ma, China Satellite Navigation Office.
  80. ↑ "APPLICATIONS-Transport". http://en.beidou.gov.cn/WHATSNEWS/202006/t20200623_20692.html. 
  81. ↑ Howell, Elizabeth (23 June 2020). "China launches final Beidou satellite to complete GPS-like navigation system" (in en). https://www.space.com/china-launches-final-beidou-navigation-satellite.html#:~:text=China%20successfully%20launched%20the%20final,Launch%20Center%20in%20southwest%20China.. 
  82. ↑ "APPLICATIONS-Transport". http://en.beidou.gov.cn/WHATSNEWS/201806/t20180615_15048.html. 
  83. ↑ "European radio navigation plan (ERNP)". http://ec.europa.eu/DocsRoom/documents/28325. 
  84. ↑ 秦, 鹏霄 (2013-05-15). "S频段信号的研究". 第四届中国卫星导航学术年会. http://gb.oversea.cnki.net/KCMS/detail/detailall.aspx?filename=wxdh201305002012&dbcode=CPFD&dbname=CPFDREF. 
  85. ↑ "我国成功发射第四颗新一代北斗导航卫星". beidou.gov.cn. 30 September 2015. http://www.beidou.gov.cn/2015/09/30/201509303994d237a4c8419e925c86df8f5e1c32.html. 
  86. ↑ "我国成功发射第五颗新一代北斗导航卫星". beidou.gov.cn. 1 February 2016. http://www.beidou.gov.cn/2016/02/01/20160201acefeef4af98428dad6b46b83a72b179.html. 
  87. ↑ "第22颗北斗导航卫星正式入网提供服务". beidou.gov.cn. 5 August 2016. http://www.beidou.gov.cn/2016/08/05/20160805be35373a002d45788fc4b8e4b798750c.html. 
  88. ↑ "第23颗北斗导航卫星入网工作". beidou.gov.cn. 30 November 2016. http://www.beidou.gov.cn/2016/11/30/201611304b14b49a9cca4afa99b25abb519a9cee.html. 

External links




Retrieved from "https://handwiki.org/wiki/index.php?title=Engineering:BeiDou&oldid=2911339"