Accurate estimation of CGCS 2000 coordinate in regional CORS

With the development of satellite-positioning technology and people´s desire for higher positioning accuracy, the current reference-centric coordinate system will be difficult to meet the demand. Taking the geocenter as the original point of geodetic coordinate system, it can be better to illustrate not only the physiognomies of the surface and their features but also the movement of the tectonic plates and space objects. Therefore, our country have established the geodetic geocentric coordinate system CGC2000 generalize it as early as possibly. It summarizes such information of the coordinate transformation as ephemeris, stations and the baseline vector, coordinate transition methods contain these algorithms, which are seven parameters, nine parameters, polynomial regression and fourteen parameters. Using the coordinates of regional CORS stations in both ITRF05 and CGCS2000 coordinate frame as simulated data, it analyzes the accuracy and reliability of the three kinds of data and the transform methods mentioned above. By comparison, we draw the following conclusions: The precision of coordinates, which are calculated by Gamit/GLOBK with the transformed ephemeris, is equivalent to that obtained with the non-transformed ephemeris; The accuracy of coordinates converted by fourteen parameter can reach centimeter and this transform method has high reliability, which adapts to the regional and global area. For moderate or small area, the method of seven-parameter is perfect one, which precision is millimeter level. What´s more, the baseline-vector converted by seven-parameter method has a higher accuracy, which is an ideal transform method.