New Empirically Derived Solar Radiation Pressure Model for Global Positioning System Satellites

We describe the development and testing of a set of new and improved solar radiation pressure models for Global Positioning System (GPS) satellites that is based on four and one-half years of precise GPS orbital data. These empirical models show improved performance in both GPS orbit fit and prediction relative to the state-of-the-art models. Orbit-fit rms is improved 80 percent for Block IIR satellites and 24 percent for Block IIA satellites. Orbit-prediction accuracy improved 58 percent for Block IIR satellites and 32 percent for Block IIA satellites. These new models are designated GSPM.04. It is shown that, after the implementation of these new models, Block IIA and Block IIR satellites perform about the same in orbit fit and in orbit prediction.