联合高低卫-卫跟踪和卫星重力梯度数据恢复地球重力场的谱组合法

GOCE采用的高低卫-卫跟踪和卫星重力梯度测量技术在恢复重力场方面各有所长并互为补充，如何有效利用这两类观测数据最优确定地球重力场是GOCE重力场反演的关键问题。本文研究了联合高低卫-卫跟踪和卫星重力梯度数据恢复地球重力场的最小二乘谱组合法，基于球谐分析方法推导并建立了卫星轨道面扰动位T和径向重力梯度Tzz、以及扰动位T和重力梯度分量组合{Tzz-Txx-Tyy}的谱组合计算模型与误差估计公式。数值模拟结果表明，谱组合计算模型可以有效顾及各类数据的精度和频谱特性进行最优联合求解。采用61天GOCE实测数据反演的两个180阶次地球重力场模型WHU_GOCE_SC01S（扰动位和径向重力梯度数据求解）和WHU_GOCE_SC02S（扰动位和重力梯度分量组合数据求解），结果显示后者精度优于前者，并且它们的整体精度优于GOCE时域解，而与GOCE空域解的精度接近，验证了谱组合法的可行性与有效性。

Spectral Combination Method for Recovering the Earth's Gravity Field from High-low SST and SGG Data

High-low satellite-to-satellite tracking (SST-hl) and satellite gravity gradiometry (SGG) employed in GOCE mission are complementary in determining the Earth’s gravity field, but how to effectively use these two types of data is a key problem for the determination of optimal GOCE gravity filed solution. The least-squares spectral combination method for recovering the Earth’s gravity field from the combination of SST-hl and SGG data is studied. The spectral combination computing models and their error estimation formulae for combining disturbing potential T and radial gravity gradient Tzz data, and for combining disturbing potential T and gravity gradient combined components {Tzz-Txx-Tyy} data are established based on spherical harmonic analysis, respectively. Numerical simulation results indicate that the optimal combined solution can be obtained from the spectral combination computing model, which can effectively take into account the accuracy and spectral characteristics with each type of data. Finally, the feasibility and effectiveness of the spectral combination method is validated from GOCE real data processing. Two Earth’s gravity field models named WHU_GOCE_SC01S and WHU_GOCE_SC02S up to degree 180 are recovered from 61 days of GOCE data, the former is solved from T and Tzz, and the latter is solved from T and {Tzz-Txx-Tyy}. The results show that WHU_GOCE_SC02S model is more accurate than WHU_GOCE_SC01S model, and both of the models are more accurate than GOCE time-wise solution, and their total accuracy are most close to GOCE space-wise solution.