Combination of free network adjustment with S- transformation and Kalman filter with original data information adjustment for displacement analysis

Abstract

To evaluate the displacement of the coordinates of the GNSS network points according to the measured data of the periods, the theory of free network adjustment has been widely applied. However, changing the stable points in the cycles if only considering the coordinate difference after the adjustment in the normal way will not be accurate because the result of the free network adjustment of the coordinates is determined with different origin points. Therefore, it is necessary to convert the coordinate system of the previous period to the coordinate system of the following period, applying S - transformation to analyze the deformation. In addition to the displacement of the points, it is necessary to define the velocity and acceleration parameters of the displacement. In this paper, a method of displacement analysis has been studied based on using GNSS network measurement data in measurement cycles and applying the theory of free network adjustment and S transformation, Kalman filtering technique and rationalizing the geodetic network adjustment theory with the error information of the original data to analyze and predict the displacement on the experimental area of the Saigon River area. The analysis concludes the shift based on the student distribution (t - distribution). In the study, static and dynamic models were considered and gave consistent calculation results. The theory has been proven to develop the Kalman filter technique for deformation analysis and prediction problems by applying GNSS technology. This result allows to expand the scope of application of GNSS technology for monitoring and analysis of landslides, subsidence and displacement of the Earth's crust on a local scale as well as a territorial extent in Vietnam, and can e data from GNSS CORS observation stations.