Dynamic orbit parameterization and assessment in the frame of current GOCE gravity models

• Validation of gravity models via an adapted dynamic orbit determination algorithm.
• Degree-wise cumulative approach in GOCE and GRACE orbit analysis.
• GRACE K-band data analysis used as an external validation tool.
• GOCE drag-free orbit system is monitored.
• GOCE high along-track orbit residuals are found over degree 165.

The role of gravity models is fundamental in satellite orbit determination representing the dynamical contribution of the observed gravity field in the equation of motion. We examine the validation of gravity models by implementing numerically an adapted dynamic orbit determination algorithm. We focus on GOCE (Gravity field and steady-state Ocean Circulation Explorer) and GRACE (Gravity Recovery And Climate Experiment) orbit analysis based on real orbital data and current GOCE gravity models. The contribution of the gravity models is implemented in a degree-wise cumulative sense, thus quantifying the band-limited performance of the individual models at satellite altitude. Furthermore, the proposed orbit analysis scheme leads to a validation of the different gravity models, providing an insight to the effect of the gravitational counterpart to the geometry of the orbit by expressing explicitly all computations to orbit perturbations defined along the three components of the orbital frame.