利用先验重力场模型求定GOCE卫星重力梯度仪校准参数

重力梯度仪校准参数的确定是GOCE重力梯度观测数据处理的关键环节。本文对GOCE卫星重力梯度观测值中的时变信号与粗差进行了分析,利用高精度全球重力场模型,确定了GOCE重力梯度观测值各分量的尺度因子与偏差,并对校准结果进行了精度评定。结果表明,在测量带宽内,海潮对重力梯度观测值影响在mE量级,与重力梯度仪的精度水平相当,陆地水等非潮汐重力场时变信号略小于海潮,量级约为10^-4E;各分量重力梯度观测值的粗差比例均大于0.2%;除EGM96模型外的其他模型对GOCE重力梯度仪进行校准后,V_xx、V_yy、V_zz、V_yz分量上尺度因子的稳定性均在10^-4量级,V_xz分量能达到10^-5量级,V_xy分量为10^-2量级,这与梯度观测值各分量的精度水平一致。

Calibration for GOCE gradiometer data based on the prior gravity models

The determination of the calibration parameters of the gravity gradiometer plays an important role in the GOCE gravity gradient data processing. In this paper, the temporal signals and outliers in the GOCE gravity gradient observations are analyzed. Based on the different global gravity field models, the scale factors and biases are determined in all the components of GOCE gravity gradients. And then the accuracy of the calibration results is validated. The results indicate that the effect of the ocean tide is at mE magnitude in the measurement band, which is equivalent to the precision of the gravity gradiometer. While the effect of the non-tide temporal signals is, with the terrestrial water is in the order of 10^-4E slightly less than that of the ocean tide. The outliers in all the gravity gradient components are larger than 0.2%. After the calibration using global gravity field models except EGM96, the stability of scale factors in the V_xx,V_yy,V_zz,V_yz components reaches 10^-4 magnitude. And the V_xz component reaches 10^-5 while that of the V_xy component is about 10^-2, which are in accordance with the accuracy differences of the gradient components.