Improved Modeling of the Solar Radiation Pressure for the Sentinel-6 MF Spacecraft

The Sentinel-6 Michael Freilich (MF) spacecraft is the latest in a 30-year series of reference ocean altimeter missions, requiring high accuracy precise orbit determination (POD). This paper develops two improvements in solar radiation pressure (SRP) modeling for this spacecraft – an estimated macromodel and an empirical solar radiation pressure (SRP) table, that result in better orbit accuracy. The challenges of estimating highly coupled SRP effects and antenna calibrations for the largely yaw-fixed Sentinel-6 MF spacecraft are addressed through constrained dynamic orbit solutions. Using more than 500 days of data, we demonstrate improvements in the consistency of drag and solar scale estimates, antenna calibrations, measurement residuals, and orbit precision. Reduced-dynamic, ambiguity-resolved POD solutions with the new SRP models show improvement in comparison with independent Satellite Laser Ranging tracking measurements from 8.6 to 8.1 mm (RMS).