Transformation models for three-dimensional astrogeodetic cartesian coordinate system and comparison of the techniques used for determining outlier measurements groups

SUMMARY Transformation Models For Three-Dimensional Astogeodetic Cartesian Coordinate Systems and Comparison of The Techniques Used For Determining Outlier Measurements Groups There has been always a need for a common coordinate system to base all the measurements on the Earth; therefore, various coordinate systems have been defined to meet this expectation. In parallel to recent technological developments, new measurement and estimation techniques have been introduced. Coordinates of the points, which were initially defined and used as two-dimensional coordinates, have been started to be directly obtained as three-dimensional coordinates. Transformation models defined by the relationships between three-dimensional Cartesian coordinate systems have been one of the main objectives of the applications in geodesy. Making large number of measurements to increase the accuracy and reliability has always been an essential principal in geodetic studies. In order to find the best solution for the measurements, the Least Square Adjustment Method (LSAM) is generally used, but the measurements still contain some errors. Undetermined outlier measurements impair the results produced by the LSAM. Therefore, traditional methods using LSAM results fail to determine more than a single measurement and they spread the blundering to other measurements. Also, another drawback of such techniques is their iterative nature to eliminate the outlier measurements from the data set. In order to get over these drawbacks and determine the outlier measurements, robust estimation and fuzzy logic methods have been introduced. Methods investigated in this study are applied to a test network using in-house computer programs and the results are analysed to determine the advantages and disadvantages of the techniques. Keywords: Three-dimensional Cartesian Coordinate Systems, Transformation Models Coordinate Systems, The Least Square Adjustment Method, Outlier Determination Methods, Traditional Approaches, Robust Estimation Method, Fuzzy Logic Technique. VII