CGCS2000 Robust Coordinate Transformation And Its Application

The essence of three-dimensional coordinate transformation is to use the two sets of coordinates of the common point in the source coordinate system and the target coordinate system,and the coordinate information of other non-common points in the source coordinate system to estimate other non-common points in the target coordinate system.coordinate.In the traditional seven-parameter transformation model,the coordinate error and the non-common point coordinate error of the common point in the target coordinate system are ignored,which leads to the inaccuracy of the 7 parameters calculated by the traditional Bursa 7-parameter model.Or,when the distribution is uneven,or the coordinate conversion is performed when the coordinates of the non-common points outside the common point area are coordinate-transformed,there is a gap in the common point area where the7-parameter is obtained.In the actual solution process,the common point and the non-common point of the source coordinate system have a gross error in addition to the coordinate error.The traditional least squares method is when the observed random error is normally distributed.The optimal solution,but when there is systematic error or gross error in the observed value,the least squares method is no longer applicable.This paper mainly discusses the above problems,comprehensively analyzes the research situation and shortcomings of coordinate transformation technology at home and abroad.Based on the introduction of the coordinate system used since the founding of the country in 1949,the paper explores the application of the 2000 national geodetic coordinate system as an opportunity to explore the stable coordinates of CGCS2000.The method of coordinate transformation is given to the mutual conversion model of different coordinate systems under the same reference and the coordinate transformation model under different references.Based on the theory of robust estimation,a robust transformation method of CGCS2000 coordinates is proposed.Taking the disease resistance and the resistance of the coordinate transformation as the starting point,the influence of the ill-conditioned and gross error of the equations on the conversion results is studied,and the robust coordinate transformation is realized to improve the Bursa seven-parameter model.At the same time,all the point errors and conversion parameters are considered.The random error of the coefficient matrix is combined with the three-dimensional coordinate transformation parameters and prediction to realize the application ofrobust three-dimensional coordinate transformation,and the corresponding software is compiled to process some sample data for analysis.Through experimental analysis,it can be seen that when the observations contain gross errors,the robust estimation method that takes into account the gross error and error correlation performs better,and the accuracy of the acquisition seven parameters is higher.The converted target obtained by the robust coordinate estimation method is obtained.The coordinate point is more accurate and the resistance is better.