GPS水准测量外文翻译文献.docx

GPS水准测量外文翻译文献Analyzing the Deformations of a BridgeUsing GPS and Leveling DataAbstract. The aim of this study is analyzing 1D (in vertical) and 3D movements of a highway viaduct, which crosses over a lake, using GPS and leveling measurement data separately and their combination as well. The data are acquired from the measurement campaigns which include GPS sessions and precise leveling measurements, performed with six–month intervals for two years.In 1D analysis of the (vertical) deformations, the height differences derived from GPS and leveling data were evaluated. While combining the height–difference sets (GPS derived and leveling derived) in the third stage of 1D analysis, Variance Component Estimation (VCE) techniques according to Helmert’s approach and Rao’s Minimum Norm Quadratic Unbiased Estimation (MINQUE) approach have been used.In 3D analysis of the deformations with only GPS data classical S–transformation method was employed.The theoretical aspects of each method that was used in the data analyses of this study are summarized. The analysis results of the deformation inspections of the highway viaduct are discussed and from the results, an optimal way of combining GPS data and leveling data to provide reliable inputs to deformation investigations is investigated in this study.Keywords . GPS, Leveling, Deformation Analysis, Variance Component Estimation, S–Transformation1 IntroductionIt has a considerable importance to have the movements of an engineering structure within certain limits for the safety of the community depending on it. To determine whether an engineering structure is safe to use or not, their movements are monitored and possible deformations are detected from the analysis ofobservations. An appropriate observation technique, which can be geodetic or non–geodetic (geotechnical–structural) according to classification in Chrzanowski and Chrzanowski (1995), is chosen with considering the physical conditions of the observed structure (its shape