Transformation of 3D GPS Cartesian coordinates to ED50 using polynomial fitting by robust re-weighting technique

The purpose of this study is the solution of the transformation problem between the GPS networks and old geodetic networks based on the national coordinate system alternatively by a 3-dimensional robust polynomial transformation (3D.R.P.T). This study focuses on and probes 3D similarity (3D.S.T), 3D polynomial transformation with least squares estimate as equal-weighted (L.S.3D.P.T), 3D polynomial transformation based on weight with the inverse of the distances of common points to the centre of gravity (W.L.S.3D.P.T) and robust estimate approaches that are re-weighted and are based on iterative solution. A detailed mathematical model and solution algorithm of the proposed model is given, and it has been applied in a test area covering the city borders of Istanbul for which its results were studied and compared to other three methods.