Estimation of the Datum Transformation Parameters between Wgs-84 and Everest Ellipsoid for Gujarat Region of Western India

要旨

Indian topographical maps, prepared by Survey of India, is all based on the Indian Geodetic Datum: the Everest Ellipsoid. Using the Global Positioning System (GPS) surveying technique, the coordinates are obtained on the global datum: World Geodetic reference System (WGS-84). Hence, in order to locate a ground point using GPS on the Indian topographical maps, it is essential to establish a relation between these two datums. A case study for this has been carried out in the Gujarat region of Western India. In this paper, details of this study, along with some salient results have been presented. Three and four parameter transformations have been attempted, and the parameters are estimated using coordinate of the Great Trigonometrical Triangulation (GT) station points, re-observed using GPS. GPS survey was conducted at four GT stations in the Gujarat region, in order to estimate the regional transformation parameters. The estimated errors for the transformation parameters, in the X, Y, and Z coordinates, are 1.21 m, -0.37 m, and -2.99 m, respectively.