China's home-grown satellite navigation system launched a limited positioning service Tuesday, the official Xinhua news agency said, as the country seeks to break its dependence on foreign technology.

China started building its space-based navigation network in 2000 to stop it having to rely on the US-controlled Global Positioning System (GPS), and previous reports have said it will provide a worldwide service by 2020.

The Beidou, or Compass, navigation system was now providing services for China and "surrounding areas", Xinhua said, and Beijing would launch another six satellites in 2012 to expand it to most of the Asia-Pacific region.

The first Compass satellite was launched in April 2007, after four other experimental satellites were placed in orbit earlier in the decade. It is not clear how many satellites have been launched so far.

Once completed, the system will have 35 satellites developed using Chinese technology, and will provide services for mapping, fishery, transport, meteorology and telecommunications, state media have said.