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 South China Sea, a move observers say is meant to consolidate Beijing’s control of the contested waters.

Collin Koh, a maritime security specialist at Singapore’s Nanyang Technological University, said various technical and climatic factors prevented China’s existing satellite system from giving complete coverage of the disputed waters.

“The new satellite remote sensing plan … constitutes just a facet of the overall efforts China has been making in improving its sense-making ability in the South China Sea,” Koh said.