Local Geoid Computation by the Spectral Combination Method
Local Geoid Computation by the Spectral Combination Method
复制标题
谱组合法的局部大地水准面计算
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
Jürgen Müller
中科院分区：
文献类型：
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作者：
O. Gitlein;H. Denker;Jürgen Müller
研究了利用全球重力场模型、即将进行的GOCE卫星的径向重力梯度和重力异常确定德国下萨克森州当地大地水准面的光谱组合方法。本研究的主要目的是测试该方法对GOCE数据产品的有效性。为了验证该方法的有效性和数值精度，基于EGM96重力场模型进行了闭环系统仿真计算。利用相应的谱权函数将重力场信号分解为长、中、短三个波长分量。长波信息(n=30阶)由全球位势模型计算得到，中波长部分(n=30−130)由GOCE高度(250公里)的径向重力梯度得到，高频部分(n=130−360)由地球重力异常得到。将改进的球面巴特沃斯滤波器和余弦滤波器作为谱权函数进行了测试。讨论了闭环仿真的结果，并考虑了输入数据集的委托误差和遗漏误差，进行了误差分析。
The spectral combination method is investigated for the determination of a local geoid in Lower Saxony (Germany) using a global geopotential model, radial gravity gradients from the upcoming GOCE satellite mission, and gravity anomalies. The main goal of this study is to test the method with regard to the validation of GOCE data products. In order to prove the effectiveness and numerical accuracy of the method, the computations are done in a closed-loop simulation based on the EGM96 geopotential model. The gravity field signal is decomposed into long, medium and short wavelength components using corresponding spectral weight functions. The long wavelength information up to about degree n = 30 is computed from a global geopotential model, the medium wavelength part (n = 30−130) is taken from radial gravity gradients at GOCE altitude (250 km), and the high frequency part (n=130−360) is derived from terrestrial gravity anomalies. The modified spherical Butterworth filter and a cosine filter are tested as spectral weighting functions. The results from the closed-loop simulation are discussed, and an error analysis is done considering the commission and omission errors of the input data sets.