由GOCE引力梯度张量不变量确定卫星重力模型的半解析法

Approach for Determining Satellite Gravity Model from GOCE Gravitational Gradient Tensor Invariant Observations

提出了利用半解析方法解算重力场与稳态海洋环流探测器(gravity field and steady-state ocean circulation explorer,GOCE)引力梯度张量不变量观测值来恢复全球卫星重力模型的方法,该方法比最小二乘方法效率高,同样可给出模型的验后方差。推导了半解析法快速解算引力梯度张量不变量的理论公式,给出了该方法利用卫星重力梯度观测数据快速求解重力场模型的基本步骤。利用89.5°倾角圆形严格重复轨道上的模拟梯度观测值验证了半解析方法用于张量不变量解算的理论严密性,并利用GOCE任务61d梯度仪坐标系(gradiometer reference frame,GRF)下无噪声和有噪声的I2和Vzz模拟观测值进行了模型反演和结果分析。结果表明,利用I_2观测值求解模型的精度略优于仅用Vzz分量解算模型的精度。

A semi-analytical（SA）approach is proposed to recover a gravity field model from the GOCE tensor invariant observations.The SA approach is more efficient than the least-squares method,and could provide the posterior variance of estimated coefficients.The formulas for gravity field model determination from tensor invariant observations based on SA approach were derived and a corresponding procedure for estimation of the satellite gravity model from satellite gravity gradient observations are described.Testing results from the simulated error free observations along the circular orbit with the inclination 89.5°show that applying the SA approach to process tensor invariant observations is theoretically rigorous.Using the simulated observations with or without errors in gradiometer reference frame（GRF）along the one repeat cycle GOCE real orbit,we recovered the gravity field models from the I2 and Vzzcomponents respectively.Numerical analysis results show that the solution fromI2 was slightly better than the one fromVzzcomponent,which verified the feasibility of the method.