摘要
频域输入输出法在计算效率上的优势,使其在局部重力场逼近中受到广泛关注.选取Moritz协方差函数模型,通过非线性最小二乘法拟合协方差函数模型系数,采用相关法估计功率谱密度函数,顾及"移去-恢复"技术,构建基于频域输入输出法的大地水准面精化模型.设计了以EGM2008模型重力异常为基础数据,计算大地水准面高的仿真试验,量化分析了相关距离选取的问题.结果表明:只要选取的相关距离不小于1倍的相关长度,该模型即能满足当前厘米级大地水准面的要求;在此基础上,对该模型进行了精度评估,在3种不同观测噪声下算得的大地水准面精度高分别为7.15,8.37和8.91cm,优于同等观测精度下Stokes法的计算结果.
The input-output method in frequency domain is widely concerned in the approximation of local gravity field because of the advantages of its computational efficiency.Moritz covariance function model,the coefficients of which can be determined through nonlinear least square,was selected to estimate the power spectral density function through the correlation method.Taking into account the remove-restore technique,the refined geoid model based on the input-output method was constructed.The simulation experiment that EGM2008 gravity anomalies are used as the basic data to calculate the geoid was designed,and the selection of the correlation distance was quantitatively analyzed.The results show that the model can meet the requirement of the centimeter-level geoid as long as the correlation distance is no less than twice the correlation length.On this basis,the precision evaluation of the model was conducted,and the geoid accuracies calculated under the three kinds of different observation noises are 7.15,8.37 and 8.91 cm respectively,which are better than the Stokes＇ s results under the same observation precision.
出处
《中国矿业大学学报》
EI
CAS
CSCD
北大核心
2016年第6期1278-1284,共7页
Journal of China University of Mining & Technology
基金
国家自然科学基金项目(41474012)
国家重点基础研究发展计划(973)项目(613219)
