CGCS2000框架维持方法分析

针对目前国内各GNSS应用在归算到2000国家大地坐标系（CGCS2000）时常采用强制符合及拟稳平差方法存在的问题及局限性，利用国家测绘地理信息局收集的全国近1 800个连续运行参考站（Continuously Operating Reference Stations，CORS）连续观测1个月的数据进行数据处理得到的基线解，分别基于强基准拟稳平差方式及顾及板块运动的速度场归算方法获得测站在CGCS2000下的坐标，分析两者的差异及误差分布情况，指出对于省级CORS站纳入CGCS2000的情况，采用强制符合拟稳平差方法所基于的基准站必须考虑板块的运动趋势进行CGCS2000归算，否则平差结果与CGCS2000最大差异将达到dm量级。

CGCS2000 Maintain Methods Analysis

As an existing method, Quasi_Stable Adjustment which is often used to align local CORS position to CGCS2000 at present, has some limitation. This paper focuses on studying the methods of calculating the real position of GPS stations at the reference epoch of CGCS2000 from GPS observations obtained from various observing times, two methods are introduced here. One is to align the position of GNSS stations to CGCS2000 through adjustment with coordinates of CGCS2000 reference stations constrained tightly, while the other method is to transform the coordinates of the GNSS stations to CGCS2000 through their velocities. In order to demonstrate the difference between these two methods, nearly 1800 CORS's observations about one month collected from 30 provinces in China were processed and transformed with the two methods. The conclusion derived from the results analysis shows that the maximum transformed difference between Quasi_Stable Adjustment and CGCS2000 will be dm.