地形对确定高精度局部大地水准面的影响

Abstract

以计算香港大地水准面为例 ,着重研究了以下几点 :①DTM的分辨率对地形改正的影响 ;②质量柱体地形模型与质量线地形模型对计算地形改正的差异 ;③采用Helmert凝聚改正法 ,计算地形对大地水准面的间接影响 ;④比较经典Stokes Helmert方法与Sj¨oberg方法计算地形对大地水准面的影响 For the determination of high precise (centimeter level) local gravimetric geoid, it is very important to determine the terrain effects on geoid undulations. The effect of grid spacing of digital topographic model on terrain corrections and geoid undulations and the indirect terrain effect on geoid undulations are studied, as well as the effect of mass prism and mass line topographic models on terrain corrections. And the differences of the total terrain effect on geoid undulations by classical Stokes-Helmert method and Sjberg’s method are discussed and compared. Finally, some practical conclusions and suggestions are drawn from the test results of Hong Kong geoid determination.