The ground surface is literally the base of all social activities.
This technology detects sinking/uplifting of the ground surface as well as tilting of buildings.
It uses the data of SAR satellites, which illuminate radio signals onto the ground and receive reflected waves to obtain information on the ground surface.
By comparing reflected signals received at the same location from the same target but at different timings the phase difference can be detected, which is then used to measure the displacement of the ground surface.
Without setting up any standing point on the ground, we can observe a displacement as small as 1 millimeter in vertical and 1 meter in horizontal directions.
In addition to detecting the ground surface displacement, InSAR can be used to detect displacement of bridges, tunnels, and other buildings. This is useful in monitoring all work processes from construction, operation, and maintenance as well as in identifying any high risk areas of land subsidence, landslide, and other disasters.
