China on Tuesday began offering its own satellite navigation system to users, as an effort to move away from the nation’s reliance on the U.S.-built NAVSTAR GPS network.

Beidou now offered location, timing and navigation data to China and surrounding areasannounced the project’s spokesman Ran Cheng. China has been working on the system since 2000 to provide an alternative to the US government-run Global Positioning System (GPS). The move should make China’s military less dependent on foreign technology. A launch earlier this month delivered the tenth of Beidou’s satellites into orbit.

Beijing plans to send a further six satellites into space by 2012 to extend the system to most parts of Asia, and then expand the network to a total of 35 satellites offering global coverage by 2020. Interested parties are invited to study a test version of the project’sInterface Control Document which has been placed online

The first BeiDou system, officially called BeiDou Satellite Navigation Experimental System, or known as BeiDou-1, consists of 3 satellites and has limited coverage and applications. It has been offering navigation services mainly for customers in China and from neighboring regions since 2000.

The second generation of the system, known as Compass or BeiDou-2, which will be a global satellite navigation system consisting of 35 satellites, is still under construction. It became operational with coverage of China in December 2011.[1] It is planned to offer services to customers in Asia-Pacific region by 2012 and the global system should be finished by 2020.

China said building its own satellite navigation system was necessary in order to further economic development, according to Ran Chengqi, a spokesman for the Beidou system. “If there is no independent control of the satellite navigation system, the security of China’s economic and social development lacks dependable protection,” he said during a Tuesday media briefing posted online.

Beidou, however, is compatible with existing satellite navigation systems, according to Ran. Initially the Beidou system will only serve China and neighboring countries. But by 2020, the system will offer global coverage, by using a total of more than 30 satellites. The service is free of charge and has already been in use by different domestic industries since Beidou was first started in its early stages back in 2000.

China made Tuesday’s announcement as a way to also encourage both domestic and foreign companies to develop satellite navigation devices using the Beidou system. Authorities have made technical information about the system available at (An English document of the system can be found here.)

Beidou is accurate within 25 meters. But its accuracy will improve to 10 meters by the end of next year. The system also allows users to send short messages, but officials at Tuesday’s announcement did not reveal details of how the feature worked.

Missile guidance

Beidou – which translates as the Big Dipper – promises to offer civilian users positioning information correct to the nearest 10 metres, measure speeds within 0.2 metres per second, and provide clock synchronisation signals accurate to 0.02 millionths of a second. The Chinese military will be able to obtain more accurate data.

A 2004 study by Geoffrey Forden, a researcher at the Massachusetts Institute of Technology, suggested that Beidou could be used to target cruise missiles against Taiwan if a war broke out over the territory. Having its own system would protect China against the risk that the US could turn GPS off. A 2011 report for the website suggested the network could also be used to guide drones to destroy foreign naval forceswere China to come under attack.

However, Beidou’s developers also stress day-to-day benefits for the public. They told China Daily that the system could create a 400 billion yuan ($63.2bn, £40.4bn) market in related applications for the automotive, telecommunications, fishing and other industries by 2020. The European Union’s Galileo system aims to offer a partial service within the next two years

Alternative systems

Mr Ran also noted that the system is compatible and interoperable with the world’s other navigation systems. Beyond GPS, Russia operates the Glonass network. It recently launched a series of satellites to cover gaps in its system and reported earlier this month that it once againcovered 100% of the Earth’s surface. The EU is also developing its own system – Galileo. The first of its operational satellites entered orbit in October. The European Space Agency said the network should be completed in 2019.

Meanwhile, defence developer Lockheed Martin is working to upgrade the US’s system to GPS III.

Source : BBC, pcworld, wikipedia