The authors are developing a real-time displacement monitoring system by using the Global Positioning System to assess the stability of large slopes. This paper presents the results of field experiments for long-term continuous measurements and discusses the stability and properties of the data obtained by the system. The measured values include random errors, deviations, and largely scattered errors. In order to choose the acceptable data from the original data, including the above errors, a data processing method is proposed in this paper. Applying the proposed method, the system can provide stable and reliable data.
Field experiments for displacement measurements were also conducted to verify the applicability of the system to continuous displacement monitoring. It is concluded that the system can detect at least 5 mm displacements in the horizontal direction and 10 mm displacements in the vertical direction in real time. The accuracy is better than that of the conventional off-line GPS method.
