Structure deformation monitoring is the process of monitoring a surface of an object or structure (e.g. a bridge or a dam) to determine if they have become depressed into the surface on which they are mounted. Deformation monitoring can be used to detect ground subsidence. Ground subsidence is the movement of the surface of the earth towards the center of the Earth.

Bridge deformation monitoring is the process of monitoring a surface of a bridge to determine if it has changed shape or if it has become depressed into the surface on which they are mounted. GPS systems can be used to detect structural changes in a bridge. Several GPS receivers are located at various points on a bridge that can be used to detect if the bridge structure begins to change.