Aerial photo taken on Jan. 8, 2020 shows the staff members of the Haikou navigation mark office changing anchor chain for the old buoy on the sea patrol ship "Haixun 172" in Qiongzhou Strait, south China. Staff members of the Haikou navigation mark office of the Navigation Guarantee Center of South China Sea (NGCS) of the Ministry of Transport updated the No. 1 buoy in Xiuying Port of Haikou by installing a telemetry and telecontrol unit based on Beidou Navigation Satellite System and Beidou AIS (Automatic Identification System) physical navigation mark on Wednesday. In the past four month, about 112 buoys and 6 beacons in the Qiongzhou Strait have been maintained and updated, which realized the fully coverage of telemetry and telecontrol system on the navigation marks in waters in the strait. The navigation and transportation efficiency are expected to be improved as the Spring Festival travel rush is upcoming. (Xinhua/Yang Guanyu)