China's southern island province of Hainan has said it is preparing to launch a series of satellites in the later half of 2019, in two phases, to assist remote sensing coverage.

The Sanya Institute of Remote Sensing on Tuesday approved technical plans for three optical satellites in the first phase and one in the second phase.

There are a total of six optical satellites in the Satellite Constellation Program, a commercial space project launched on Dec. 14, last year.

The program also includes two hyperspectral satellites and two SAR satellites by 2021, for conducting remote-sensing over the South China Sea.

Yang Tianliang, director of the institute, said the network would be used to provide data services in navigation, fisheries and emergency rescue.