联合EGM2008模型重力异常和GOCE观测数据构建超高阶地球重力场模型SGG-UGM-1

The Determination of an Ultra-high Gravity Field Model SGG-UGM-1 by Combining EGM2008 Gravity Anomaly and GOCE Observation Data

本文研究了联合卫星观测数据和重力异常数据确定超高阶重力场模型的理论方法,并使用EGM2008模型重力异常和GOCE(gravity field and ocean circulation explorer)观测数据构建了重力场模型SGG-UGM-1。重点研究了由球面格网重力异常快速构建超高阶重力场模型的块对角最小二乘方法,将OpenMP技术引入到块对角最小二乘中以提高计算效率,并基于模拟数据验证了方法及算法和软件模块的正确性。采用本文制定的联合解算策略,利用GOCE重力卫星观测数据构建的220阶次法方程和EGM2008模型重力异常构建的2159阶次块对角法方程,联合求解了2159阶次的重力场模型SGG-UGM-1。将SGG-UGM-1与EGM2008、EIGEN-6C2、EIGEN-6C4等超高阶模型在频谱域内进行了比较分析,结果表明SGG-UGM-1相对参考模型的系数误差较小,且在220阶次内的系数精度相比EGM2008模型有了提高。采用中国与美国的GPS/水准数据和毛乌素测区的航空重力观测数据对这些模型进行了外符合精度的检验。检核结果表明,在中国区域,SGG-UGM-1模型大地水准面的精度在EIGEN-6C2和EIGEN-6C4两个模型之间,优于GOSG-EGM模型和EGM2008模型,与美国区域几个模型的精度相当。利用毛乌素测区的航空重力数据对几个模型进行了检核,结果表明SGG-UGM-1模型计算的重力扰动精度与EGM2008、EIGEN-6C4模型相当,优于GOSG-EGM模型和EIGEN-6C2模型。

The theory and methods of the determination of an ultra-high gravity field model by combination of satellite observation data and gravity anomaly data are studied.And an ultra-high gravity field model named SGG-UGM-1 is computed using EGM2008 derived gravity anomaly and GOCE observation data.The block-diagonal least squares(BDLS)method for quickly estimating an ultra-high gravity field model is researched and the corresponding software module is validated by numerical experiments.OpenMP technique is introduced into the BDLS program,which improves computing efficiency dramatically.An ultra-high gravity model SGG-UGM-1 complete to degree and order 2159 is derived using the proposed calculation strategies.The fully occupied normal equation system up to degree and order 220 formed by GOCE satellite data and the block-diagonal normal equation system up to degree and order 2159 formed by EGM2008 gravity anomaly data are used for the combination.Comparison among the models SGG-UGM-1 and EGM2008,EIGEN-6C2,EIGEN-6C4,GOSG-EGM in frequency domain has been done,which shows that SGG-UGM-1 is close to the reference models and that the coefficients lower than degree 220 of SGG-UGM-1 are more accurate than that of EGM2008.The models are also validated by GPS-leveling data in China and America and airborne gravity data in Maowusu surveying area.The results show that in China the accuracy level of SGG-UGM-1 derived geoid is between EIGEN-6C2 and EIGEN-6C4,and better than GOSG-EGM and EGM2008,while in America they are almost the same.In Maowusu area the accuracy level of SGG-UGM-1 derived gravity disturbance is almost at the same accuracy level with EGM2008 and EIGEN-6C4 and better than GOSG-EGM and EIGEN-6C2.