Comparison of the Regional Geoid Undulations Determinated by Geopotential Models
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摘要: 分析了EGM2008、EGM96、GGM02等几种地球重力位模型的阶方差,为得到各模型中长波分量和短波分量的精度,利用研究区域内GPS水准数据分别对所选模型120阶和360阶计算得到的大地水准面高进行了比较,又考虑到地形和实测重力数据缺失对大地水准面的影响,把研究区域划分为平原和山地丘陵两部分,并比较了两个地区内参考点上模型计算值的精度,利用最小二乘原理对模型计算值进行了拟合改正。Abstract: The analysis of the degree variances of the geopotential models(EGM2008、EGM96、 GGM02 et al)were presented.In order to generating the accuracies of the long-medium and short medium components of the models,the geoid undulations computed by the models up to degree 120 and 360 were evaluated combing with the GPS leveling data in the research area.Considering the effect of the topography on the geoid and the deficiency of the observed gravity data,the research area was divided into the flat part and the mountainous part roughly,and then the model values on the reference points were compared in each part.Finally a least square fitting was used to correct and modify the model values.The results were showed as follows,EGM2008 was the most accurate model with respect to the potential coefficients.In the fist 120 degree the accuracy of the values from the model EGM2008 was quite identical with those from GGM02C_EGM96,as well as EGM2008 was the best in the degree of 360.The standard deviation in the mountainous areas was larger than that in the flat areas obviously and EGM2008 was also the best model in two topographic conditions.Compared to the model values the fitting values were improved,but the accuracy was not as good as that in flat part.
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Keywords:
- geopotential model /
- potential coefficient /
- geoid undulation
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