Research On Establishing Method Of Independent Coordinate System Associated With CGCS2000

At present,China Geodetic coordinate system is widely used in China Before that,it has gone through the 1954 Beijing coordinate system constructed in the 1950 s and the1980 Xi'an coordinate system constructed in the 1980 s.It is also a process from the reference center coordinate system to the geocentric coordinate system related to the international earth reference frame.The 2000 China Geodetic Coordinate System has played a key role in the unified and coordinated development of the country,but the unified use of CGCS2000 in urban planning,construction,management and engineering construction cannot meet the corresponding accuracy requirements,especially in some high-altitude areas.There is a big deformation problem.Therefore,the country requires the establishment of a local independent coordinate system associated with CGCS2000 to meet the above work requirements.At present,most regions have established local independent coordinate systems related to CGCS2000,but at the same time there is a problem that the old and new coordinate systems are not related,and a large number of preliminary surveying and mapping results need to be converted.Therefore,how to establish a local independent coordinate system based on the CGCS2000 reference ellipsoid,which can be used in fusion with the original coordinate system and seamlessly docked,has become an important research direction.The paper introduces the concepts and methods of reference ellipsoid,ground observation deformation,Gaussian projection,ellipsoid transformation,CGCS2000,etc.,through the study of the method of establishing an independent coordinate system,it is proposed to use the CGCS2000 reference ellipsoid as the basis of the ellipsoid and the original independent coordinates The plane distance between the control points of the system is taken as the ground observation value,and the local independent ellipsoid is established by the ellipsoid expansion method,and a new local independent coordinate system is established for fusion with the original local independent coordinate system through coordinate conversion.The feasibility of this method is verified based on the engineering data and data when the local independent coordinate system was established in D city in the plateau area.In this process,the common methods for obtaining the CGCS2000 geodetic coordinates are compared.According to the Gaussian projection deformation formula of the ground observation side length,the optimal compensation projection surface elevation and the central meridian are selected,and a new local ellipsoid based on the CGCS2000 reference ellipsoid is established.Finally,The coordinate conversion of the Gaussian projection coordinates of the control points based on the new local ellipsoid obtains the results of the new local coordinate system,and a comparative analysis with the results of the original local independent coordinate system shows that the results obtained by using the method in this paper are very consistent with the results of the original local coordinate system.High,new and old results can be used together,greatly reducing production costs,reaching the expected vision,and having a certain degree of feasibility.