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{{Article Infobox2
{{Article Infobox2
|Category=Other Regional
|Category=Other Regional Systems
|Title={{PAGENAME}}
|Editors=GMV
|Authors=GMV.
|Level=Basic
|Level=Basic
|YearOfPublication=2011
|YearOfPublication=2011
|Logo=GMV
|Logo=GMV
|Title={{PAGENAME}}
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There are nowadays three regional navigation satellites systems under development: the Japanase [[QZSS]], the Indian [[IRNSS]] and the Chinese BeiDou. The first two are explained in dedicated articles and BeiDou system is going to be explained next.


There are nowadays three regional navigation satellites systems under development: the japanase [[QZSS]], the indian [[IRNSS]] and the chinese BeiDou. The first two are explained in dedicated articles and BeiDou system is going to be explained next.
==BeiDou-1==
 
[[Image:Beidou_navigation_system.png‎|BeiDou Logo|thumb|200px]]
==BeiDou==


BeiDou is the chinese regional navigation system to be expanded into the global [[COMPASS General Introduction|COMPASS]] Navigation System. In fact, the initial phase of the COMPASS system is the implementation of the BeiDou regional system.
BeiDou-1 is the Chinese experimental regional navigation system. In 1994, the Chinese government authorized to start the development and deployment of an experimental satellite navigation system based on the twin-satellite navigation system. The two GEO satellites, Beidou 1A and Beidou 1B, were launched in 2000. The system began to provide positioning service in late 2001. In May 2003, the successful launch of  BeiDou-1C also meant the establishment of the BeiDou-1 system. The BeiDou-1 service is available to civilian users since 2004<ref name=Chinese_today>[http://sinodefence.com/ Compass Satellite Navigation System (Beidou), on Sinodefence.com, updated on August 6th, 2011.] </ref>, and the system services and performance characteristics at this time (2004) were:<ref name='Rome'> Compass/BeiuDou status presentation in  Rome (Italy), June 11, 2009.</ref>
* Positioning: 100m (1σ); 20m (1σ, with reference stations).
* Regional Service short message service (SMS): up to 120 Chinese characters.
* Timing: 20 ns.


<gallery widths="170px">
===Method of Operation===
Image:Beidou_navigation_system.png‎|COMPASS/BeiDou Logo
</gallery>


By April 2011, the initial phase of COMPASS system has been completed with a constellation of 4 GEO satellites and 3 IGSO satellites. During 2011, the system is going to launch another 4 BeiDou Navigation Satellites, providing initial passive positioning navigation and timing services for the whole Asia-Pacific region, this will complete the BeiDou regional system by 2012.<ref name='Compass_Munich'>''COMPASS Status Presentation'', Munich Satellite Navigation Summit March 2011.</ref>
The following procedure is used (extracted from article ''Compass Satellite Navigation System (Beidou)'', on Sinodefence.com<ref name=Chinese_today/>):


The list of BeiDou satellites as April 2011 can be found in article [[COMPASS Space Segment]]. During 2011, the system is going to launch another 4 Beidou Navigation Satellites, providing for the whole Asia-Pacific region:<ref name='Compass_Munich'/>
''Firstly, the central control station sends inquiry signals to the users via the two satellites. When the user terminal received the signal from one satellite, it sends responding signal back to both satellites. The central station receives the responding signals sent by the user from two satellites, and calculates the user’s 2D position based on the time difference between the two signals. This position is then compared with the digital territorial map stored in the database to get the 3D position data, which is then sent back to the user via satellites using encrypted communications. The user can also transmit encrypted text messages (up to 120 Chinese characters) to the central station via the satellites.''


- initial passive positioning navigation;
''The system provides positioning data with accuracy of 100m. By using ground- and/or space-based (the 3rd and 4th satellites) differential methods, the accuracy can be increased to under 10m and the timing accuracy 100 nanoseconds. The system capacity is 540,000 users per hour, and serve up to 150 users simultaneously. As well as positioning service, the system can also transmit encrypted text messages between the central control station and the end users.''


- timing service;
''Because the Beidou 1 system requires dual-way transmissions between the user and central control station via satellites at high-altitude geostationary orbit, its user segment needs extra space for transmitter and a more-powerful battery. Therefore Beidou 1’s user segments are much bigger (20cm antenna), heavier and more expensive compared with GPS user receivers. Additionally, the number of users can be served by the system is limited by the communication capacity of the network.''


- and short message communication (120 Chinese characters per message) service.
===Applications===


The aim of the regional BeiDou system (completion expected by end of 2012) is to provide two types of services:<ref name='Compass_Munich'/>
BerDou-1 positioning service has been used in different applications, including:<ref name='Rome'/>
*Disaster Control.
*Marine application.
*Transportation application/fleet management.


* '''Open service''': a free service for civilian users with positioning accuracy of within 10 metres, velocity accuracy of within 0.2 m/s and timing accuracy of within 20 nanoseconds;
In 2008 Sichuan earthquake, around 1000 BeiDou-1 terminals provided positioning, monitoring, and emergency information services. Also in 2008, BeiDou-1 gave services for the search and rescue fleet management for Shenzhou-7 Manned Space Program<ref name='Rome'/>. Since October 2009, the Yunnan border guards are equipped with BeiDou-1 terminals.<ref>[http://en.wikipedia.org/wiki/Beidou_navigation_system BeiDou Navigation system in Wikipedia]</ref>


* '''Authorized service''':a licensed service with higher accuracy even in complex situations for authorised and military users only.
==BeiDou-2 Phase 1==


These services are available for the BeiDou coverage area, i.e. China and its neighbouring countries.
For further description of BeiDou-2 including its global service, developed in Phase 2, please check the [[COMPASS General Introduction|COMPASS]] articles.


==Notes==
==Notes==

Latest revision as of 20:47, 26 August 2018


Other Regional SystemsOther Regional Systems
Title Other Regional Systems
Edited by GMV
Level Basic
Year of Publication 2011
Logo GMV.png

There are nowadays three regional navigation satellites systems under development: the Japanase QZSS, the Indian IRNSS and the Chinese BeiDou. The first two are explained in dedicated articles and BeiDou system is going to be explained next.

BeiDou-1

BeiDou Logo

BeiDou-1 is the Chinese experimental regional navigation system. In 1994, the Chinese government authorized to start the development and deployment of an experimental satellite navigation system based on the twin-satellite navigation system. The two GEO satellites, Beidou 1A and Beidou 1B, were launched in 2000. The system began to provide positioning service in late 2001. In May 2003, the successful launch of BeiDou-1C also meant the establishment of the BeiDou-1 system. The BeiDou-1 service is available to civilian users since 2004[1], and the system services and performance characteristics at this time (2004) were:[2]

  • Positioning: 100m (1σ); 20m (1σ, with reference stations).
  • Regional Service short message service (SMS): up to 120 Chinese characters.
  • Timing: 20 ns.

Method of Operation

The following procedure is used (extracted from article Compass Satellite Navigation System (Beidou), on Sinodefence.com[1]):

Firstly, the central control station sends inquiry signals to the users via the two satellites. When the user terminal received the signal from one satellite, it sends responding signal back to both satellites. The central station receives the responding signals sent by the user from two satellites, and calculates the user’s 2D position based on the time difference between the two signals. This position is then compared with the digital territorial map stored in the database to get the 3D position data, which is then sent back to the user via satellites using encrypted communications. The user can also transmit encrypted text messages (up to 120 Chinese characters) to the central station via the satellites.

The system provides positioning data with accuracy of 100m. By using ground- and/or space-based (the 3rd and 4th satellites) differential methods, the accuracy can be increased to under 10m and the timing accuracy 100 nanoseconds. The system capacity is 540,000 users per hour, and serve up to 150 users simultaneously. As well as positioning service, the system can also transmit encrypted text messages between the central control station and the end users.

Because the Beidou 1 system requires dual-way transmissions between the user and central control station via satellites at high-altitude geostationary orbit, its user segment needs extra space for transmitter and a more-powerful battery. Therefore Beidou 1’s user segments are much bigger (20cm antenna), heavier and more expensive compared with GPS user receivers. Additionally, the number of users can be served by the system is limited by the communication capacity of the network.

Applications

BerDou-1 positioning service has been used in different applications, including:[2]

  • Disaster Control.
  • Marine application.
  • Transportation application/fleet management.

In 2008 Sichuan earthquake, around 1000 BeiDou-1 terminals provided positioning, monitoring, and emergency information services. Also in 2008, BeiDou-1 gave services for the search and rescue fleet management for Shenzhou-7 Manned Space Program[2]. Since October 2009, the Yunnan border guards are equipped with BeiDou-1 terminals.[3]

BeiDou-2 Phase 1

For further description of BeiDou-2 including its global service, developed in Phase 2, please check the COMPASS articles.

Notes


References