The monitoring of ground surface displacements plays an important role in the risk assessment of various types of slopes. The Global Positioning System (GPS) is one of the useful tools for monitoring slope behavior because it realizes the automatic and continuous measurements of three-dimensional displacements over extensive areas. However, in order to obtain highly reliable displacements under any environmental conditions, appropriate error correction/reduction methods should be applied to enhance the monitoring results. Tropospheric delays and overhead obstacles cause large measurement errors especially in steep slopes when there is a large height difference between the reference point and a monitoring point.
In this research, the GPS monitoring system, applied to monitor the displacements of a large steep slope, is examined. The monitoring has been continuously conducted for eight years. By applying error correction/reduction methods, the three-dimensional movements of the landslide could be clearly observed. This paper presents the transitions of the three-dimensional displacement components and vectors from 2014 to 2021.
