China unveils satellite network plan for South China Sea

China has unveiled a satellite network plan for round-the-clock lock on South China Sea, which experts say, is aimed at strengthening Beijing's hold on contested waters as it quietly presses on with build-up on artificial islands.

China plans to send up 10 more satellites from the southern island of Hainan over the next three years to plug surveillance gaps over the sea.

The plan surfaced on Friday after a US think tank released satellite images showing what it said was "more Chinese infrastructure built on seven artificial South China Sea islands," South China Morning Post reported.

"When completed, the satellite network would be able to monitor the South China Sea around the clock and analyse every object in the waters in detail, including the structure of vessels," Hainan Daily quoted Li Xiaoming, from the Sanya Institute of Remote Sensing and Digital Earth, as saying.

According to state-run Xinhua, "China will launch the satellites, including more sophisticated 'hyperspectral' and 'synthetic aperture radar' satellites, by 2021 to conduct round-the-clock remote-sensing over the busy waterway."

China has expanded surveillance and military facilities in the South China Sea amid competing claims from the Philippines, Vietnam, Taiwan, Brunei and Malaysia.

The Washington-based Asia Maritime Transparency Initiative said China had added 29 hectares of infrastructure to seven artificial South China Sea islands since early last year, adding the build-up suggested Beijing would develop the bigger outposts into fully-functioning air and naval bases.