Abstract: This paper analyzes and studies the update strategies and methods of the nation-wide entity coordinate results after the new CGCS2000 frame update, and provides ideas and countermeasures for the future CGCS2000 frame maintenance on aspects of the GPS station layout, data dealing methods and product accuracy possible achieved. In this paper, the data of dense CORS station abroad, which is roughly the same in terrain and area as China, can be downloaded publicly, is used to design and process the GPS observation data set with different time length and the required cm-level and decimeter-level CGCS2000 coordinate data set for this study. The improvement of CGCS2000 coordinates of astronomical geodetic network from decimeter level to centimeter level and the implementation of dynamic updating of CGCS2000 mapping products based on CORS update framework are discussed respectively. The factors that affect the accuracy realization: grid interpolation method, control point density, search range, grid spacing, etc, are fully analyzed by experiments, and it is determined that the maximum control point spacing for improving the precision of CGCS2000 coordinates for astro-geodetic points, is 2.2°, corresponding to 230km, which requires 363 points nationwide. In order to facilitate the maintenance of the regional framework and at least 4 stations guaranteed in each province (city), GPS observations need to be carried out at 2178 astronomical sites nationwide. In order to realize the dynamic update of CGCS2000 mapping products at an interval of 10 years, when 985 CORS stations are deployed, the accuracy of 5cm can be achieved when the control point spacing in the eastern, central and western regions of China is 482, 482 and 107km respectively. 2170 CORS stations are needed to deployed nationwide, which can reach the accuracy of 3cm when the density of control points in the eastern, central and western regions of China reaches 118, 374 and 75km respectively. Because the test area is geographically approximate rather than completely consistent, the conclusions obtained will differ from the reality, and only provide reference for the update mechanism of surveying and mapping products in China.

Key words: CGCS2000, coordinate product dynamic update, improve the accuracy of astro-geodetic network, optimum distribution density