Calibration for GOCE Gradiometer Data Based on the Prior Gravity Models

Abstract

The determination of the calibration parameters of the gravity gradiometer play 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 indicated 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, such as terrestrial water is in the order of 10 -4E, is slightly less than that of the ocean tide. The outliers in all the gravity gradient components are larger than 0.2%. And after the calibration using global gravity field models except EGM96, the stability of scale factors in the Vxx、Vyy、Vzz、Vyz components reaches 10 -4 magnitude, and the Vxz component reaches 10 -5 while that of the Vxy component is about 10 -2, which are in accordance with the accuracy differences of the gradient components.

Keywords

• |goce|gravity gradient|calibration|scale factor|bias