组合重力场模型的精度及其适用性分析

Analysis of the accuracy and applicability of combined gravity field model

针对EGM2008、GECO及EIGEN-6C4重力场模型存在长波误差的情况,利用GNSS/水准数据在分析EGM2008、GECO及EIGEN-6C4模型高程异常精度基础上,分析GOCO03S、GO_CONS_GCF_2_DIR_R5、GO_CONS_GCF_2_SPW_R2、GO_CONS_GCF_2_TIM_R5 4个纯卫星重力场模型与EGM2008、GECO及EIGEN-6C4模型在不同阶次组合的精度,进而选取可靠的截断阶次确定组合重力场模型。计算结果表明:与EGM2008、GECO及EIGEN-6C4模型相比,各自对应的组合重力场模型高程异常精度最优分别可达0.061m、0.054m和0.059m,对应精度提升幅度分别为18%、31%和24%,因此,组合重力场模型能提高重力场模型高程异常的精度;利用EGM2008、GECO及EIGEN-6C4模型进行高程拟合的精度与利用组合重力场模型进行高程拟合的精度相当,这说明EGM2008、GECO及EIGEN-6C4模型存在的长波段误差也可通过一定的拟合模型进行削弱。

Because of EGM2008,GECO and EIGEN-6 C4 gravity field models with a long wave error,the GNSS/leveling data is used on the basis of analyzing the height anomaly accuracy of EGM2008,GECO and EIGEN-6 C4 models.Analysis is made on the accuracy of GOCO03 S、GO_CONS_GCF_2_DIR_R5、GO_CONS_GCF_2_SPW_R2、GO_CONS_GCF_2_TIM_R5 four pure satellite gravity field models in different order combinations with EGM2008,GECO and EIGEN-6 C4 models.Then a reliable truncation order is selected to determine the combined gravity field model.The result shows that compared with EGM2008,GECO and EIGEN-6 C4 models,the height anomaly accuracy of their respective combined gravity field models can reach 0.061 m,0.054 m and 0.059 m respectively,and the corresponding accuracy improvement ranges are 18%,31% and 24%,respectively.Therefore,the combined gravity field model can improve the accuracy of the height anomaly of the gravity field model;the accuracy of height fitting using EGM2008,GECO and EIGEN-6 C4 models is equivalent to the combined gravity field model,which indicates that the long range error of EGM2008,GECO and EIGEN-6 C4 models can also be weakened by fitting the model.