China completes satellite navigation system

[Shah Khan]

Aspiring space power China completes satellite navigation system
Sat May 24,11:24 PM ET, AFP

BEIJING (AFP) - China, which hopes to be a space superpower, put a satellite into orbit, completing a home-grown navigation and positioning system that has been several years in the making, state media reported.

The Beidou satellite, which western observers have said may also have military uses, lifted off from the Xichang launching site in southwestern Sichuan province 34 minutes after midnight, Xinhua news agency said.

It was transported on board a Long March 3-A carrier rocket, just like the two previous satellites in the system, which were launched in late 2000.

With the three satellites in orbit, China now has a complete system for all-weather navigation and positioning information, serving as a "radio beacon in outer space," Xinhua said.

The system will play a key econimic role, providing services in fields such as transportation, telecommunications and meteorology and helping in preventing forest fires as well as in police work, it said.

However, the Beidou navigation system is also expected to have military uses capable of improving the accuracy of Chinese missiles, according to Western military sources.

China has been seeking to build a satellite navigation system accurate enough to be incorporated into precision munitions, similar to the smart weaponry that has helped the United States to victory in recent wars.

As part of its effort to enter the space age, China has said repeatedly it plans to send its first human into space on board a craft called Shenzhou V some time this fall.

China has so far launched four unmanned spaceflights, the last of which, Shenzhou IV, returned to earth in January after 162 hours in orbit seen as the final dress rehearsal before a manned mission.

With a successful manned space flight, China would become only the third country to send a human into orbit following the former Soviet Union and the United States.

http://story.news.yahoo.com/news?tmp...e_030525032435

[KumarM]

positioning and navigation with only 3 satellites??

[Shah Khan]

yes, thats how they describe this system...i.e. they only want to cover "China" and immediate surroundings!!
But I think more details or a map showing the actual coverage area will soon be publishesd.

China is now looking at a second generation system to provide "coverage across China."
http://www.spacedaily.com/news/china-01b.html

[Shah Khan]

Beidou ('Big Dipper') was the satellite component of an independent Chinese satellite navigation and positioning system. This was to be achieved by launching a satellite constellation in stages during 2000-2010 while developing the relevant application systems. The end result would be a Chinese indigenous satellite navigation and positioning industry. Experimental launch of the first two indigenous Beidou navigation satellites was in 2000. Beidou began in 1983 with a proposal by Chen Fangyun to develop a Twinsat regional navigation system using two geostationary satellites. The concept was proven in 1989 in a test using two in-orbit DFH-2/2A communcations satellites. This test showed that the precision of the Twinsat system would be comparable to the American Global Positioning System. In 1993, the Beidou program was officially started. Beidou used the DFH-3 bus and had similar basic performance. The final Beidou constellation was to consist of four geosynchronous satellites, two operational and two backups.

Total Mass: 2,200 kg. Total Propellants: 1,100 kg.

[Sardar Agha]

The Chinese have some way to go before they create a GPS of the same standard as Navstar or what will be Galileo.

[ImtiazA]

i thought they'd wait and go for Galileo, why even bother with one of their own??

[iqbal's]

Navigation and positioning plus other things can be done with only three satellites in orbit. This is minimum (sattelites) requirement to do the job. But it is possible!! In this case area covered should only be china. Not around world. Same as GPS but it covers all globe with 24 satellites and three as spares.

Cheers.