Component Estimation

Monitoring and analyzing deformations of large structures is included in the main interest of Geodesy Science. In deformation monitoring, terrestrial techniques such as precise levelling and/or space-based techniques such as GPS (Global Positioning System) are most commonly used measurement methods. In this paper, the subject is vertical deformation analysis of a large viaduct across a lake. The viaduct is a very attractive test object with its geological and geotechnical conditions for deformation research. With the aim of determining the deformations of this engineering structure, a control network was established and four campaign GPS measurements were carried out. GPS measurements were supported by Precise Levelling Technique. Because of that the height component is the least accurately determined GPS coordinate, due to geometric weakness of system and atmospheric errors. Analysis were done according to three different approaches; at first two approaches, deformation analysis using the height differences provided from the precise levelling measurements and from the GPS measurements were carried out separately. Then, as the third approach, the combined deformation analysis using the data from both measuremen