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China is expected to launch two navigation satellites early next year as part of a plan to build a global navigation positioning network, aerospace insiders say.

The launch of the two "Beidou" (Compass) satellites, scheduled for the beginning of 2007, is expected to cover China and parts of neighbouring countries by 2008, before being expanded into a global system, the sources confirmed over the weekend.

The planned network will be a constellation of 35 satellites, including five geo-stationary Earth orbit satellites and 30 medium Earth orbit satellites.

The system will provide two navigation services.

The service open to commercial customers will provide them with positioning accuracy within 10 metres, speed accuracy within 0.2 metres per second and timing accuracy within 50 nanoseconds.

In addition to the "open" level of service, the system will also offer safer "authorized" positioning, velocity and timing communications service.

To make the country's first-generation navigation system more compatible with other global satellite navigation systems, China is willing to co-operate with other countries, the aerospace sources said.

The United States initiated its "Navstar Global Positioning System (GPS)" in 1973, the world's first GPS service. The former Soviet Union started launching satellites for its space-based navigation system, the Global Orbiting Navigation Satellite System (GLONASS), in the early 1980s.

The European Space Agency kicked off its own positing system, the Galileo Project, in 2002.

China has sent three Compass navigation test satellites into orbit between 2000 and 2003.

The existing three-satellite Compass navigation system has played an important role in offering accurate positioning and time references for sectors including surveying, telecommunications, transportation, meteorology, forest fire prevention, disaster forecasting and public security.

China imported its first GPS receivers in the 1980s, and has become a major GPS user.

The China National Space Administration said last month the country will improve the "Beidou" navigation satellite test system, and implement the "Beidou" navigation satellite system project.

In listing the major tasks through 2010, China's Space Activities in 2006, a policy document released by the State Council Information Office on October 12, said China will "independently develop application technologies and products in applying satellite navigation, positioning and timing services."

The country will also set up a standard positioning service supporting system and popular application terminus related to satellite navigation and positioning, expanding the application fields and market.

(China Daily November 13, 2006)