回顾近20年来国内外国家局部大地水准面模型研究的概况和发展背景,采用Stokes-Helmert方法,计算了一个新的2′×2′中国重力和1985国家高程基准似大地水准面数值模型(CNGG2011),采用了100万余陆地重力数据和SRTM7.5″×7.5″地形高数据,以及649个B级GPS水准点数据。CNGG2011平均精度为±0.13m,东部地区±0.07m,西部地区±0.14m。各省区局部似大地水准面平均精度为±0.06m,东部为±0.05m,西部为士0.11m。西藏精度为±0.22m。并讨论重力大地水准面与GPS水准的关系,提出今后进一步精化我国高程基准大地水准面模型的构想。
The status and development background on the research of the local geoid of the world in the recent 20 years is reviewed in this paper. An updated 2′×2′ digital quasi-geoid model (CNGG201;) for the National Height Datum 1985 of China is computed by using Stokes-Helmert method. More than one million land gravity measurements, 7.5″×7.5″ digital elevation data from SRTM, and 649 order B GPS/leveling data are used in the computation of CNGG2011. The average accuracy ofCNGG2011 is±0.13m in China, and±0.07m and ±0.14m in eastern and western China, respectively. The average accuracy in each province is±0.06 m, and they are±0.05 m and±0.11 m in the East and the West of China respectively, and it is±0. 22 m in the Tibet area. The relationship between the gravimetric geoid and the GPS/leveling is also discussed and some strategies for geoid refinement in the future are also proposed for National Height Datum in China.