Nulinės klasės GPS tinklo deformacijų analizė

Abstract

In 1992, with the help of the Nordic Countries the created EUEF.BAL.’92 network points AKMENlŠKIAI 0311, ŠAŠELIAI 0408, MEŠKONYS 0312, DAINAVĖLĖ 0409 (Lithuanian zero order GPS network), can be included into the base network for geodynamic investigations on the Lithuanian territory. The coordinates of EUREF.BAL’92 network have been calculated twice. Wishihg to investigate in more detail the possibilities of using this network for geodynamic researches and the influence of the discrepancies on different variant adjusted results for planimetric deformations of geometrical form, the analysis of discrepancies was carried out. According to adjustment variants the obtained coordinate differences do not characterize directly the deformations of network. They illustrate the absolute changes in the location of points with respect to the points from which the coordinates have been transferred. For the analysis of planimetric deformations of geometric froms the tensor analysis method was used. Triangles are taken as final elements. For characterization of network deformations there are calculated. D1, D2 - relative values of principal deformations, i. e. interdependent perpendicular maximum and minimum deformations; (p - direction of maximum deformations of maximum deformations; G1, G2 - relative displacements of triangle gravity centre according to coordinate axes; Gm - resultant vector module of deformations according to coordinate axes; [...]- triangle turning; [...] - triangle dilatation. The results calculated are shown in table 1. It is seen from table 2 results that the triangle deformations are within the limits of measurement precision. The maximum positive quantity deformation according to directions of deformation is [...], the minimum negative quantity deformation - [...]. The triangle dilatation is from + [...] to - [...]. Although the deformations are within the limits of measurement precision, the negative quantity deformations prevail. All triangle turnings are of one direction within the limits [...].