Research On The Modeling Approach Of Velocity Field In China Continent Based On China Geodetic Coordinate System2000

The China Geodetic Coordinate System2000(CGCS2000) has been put into official useon July1,2008. Because CGCS2000stations have no velocity, unable to reflect change incrustal horizontal in China, so can’t fully express the geocentric reference frame of thedynamic and meanwhile, also can’t meet the needs of users high precision positioning. Alongwith the fast rise in number of GPS Continuous Operational Reference System (CORS) stationin China, Geodesy and geodynamics subjects growing on the basis of geographic informationneeds, to establish high precision velocity model in China is imperative. Therefore, it isnecessary for modeling approach of velocity field in China continent were studied anddiscussed based on CGCS2000.This paper, based on the introduction of Geocentric coordinate system, the internationalglobal reference system and the frame, detailed research the velocity field data acquisition,model is established and a series of problems based on CGCS2000. The main research resultsand progress:(1) firstly provides the references for converting the data processing results into China’suniform coordinates system–CGCS2000as the transformation of GPS data processingresults under different ITRF reference frame and different epochs are achieved.(2) Elaborates the principles and methods to access the velocity field data of China’scontinent on the basis of the observed data at the GPS continuous operation stations in Chinaand the international IGS stations during the years of2000-2010with the computing platformof high-precision GPS data processing software-GAMIT/GLOBK, and the analysis andcomparison have been conducted for the points of both CGCS2000and the crustal movementobservation network of China and thus calculating the reliability.(3) The method is used to obtain the high-precision measured results and velocity fielddata (the precision of velocity field value is less than±1.6mm/yr in the N direction and±1.8mm/yr in the E direction) and study the variation trend and quantity of the nationalstation in continuous operation in almost ten years, and preliminary obtained the motion trendof each station. (4) China’s mainland is divided into five blocks, including Northeast China, NorthChina, South China, Qingzang (Tibet) and Northwest China, and the study is performed onconstruction of the velocity field model of China’s mainland on the basis of three methods ofKriging interpolation, least squares collocation and movable least squares collocation, and ananalysis is conducted on the precision of the velocity field created in different blocks byutilizing the exterior verification points. The paper concludes that the least squarescollocation method has a higher precision and steady performance in most blocks (in NorthChina, South China and Northeast China). While the Kriging interpolation method has ahigher collocation precision in the blocks of Qingzang and North China and the performanceof the movable least squares collocation method is worse than other methods in all blocks.Final configuration using kriging interpolation and least squares collocation to estimatemethod to obtain the1o×1o center of grid velocity results, the two methods resultsdifference is smaller.