New and Improved Solar Radiation Models for GPS Satellites Based on Flight Data; Final rept

摘要

This report documents the analysis and results from a year-long study of a novel approach to the problem of developing solar radiation models for GPS satellites. The approach is aiming to replace the pre-launch design phase of solar pressure and heat reradiation models by a less costly and more accurate post-launch phase. The approach is also suitable for many other Earth- orbiting satellites. In this approach we exploit the fact that a collection of individual orbit solutions contains more information about the dynamics of the satellite than the information that was used to generate the individual solutions. The current GPS constellation of Block II and Block II satellites was used as a prototype for developing and validating our approach. We have used daily GPS precise ephemerides (produced routinely at JPL for the International GPS Service (IGS)) over a period of 9 months to adjust a parametrized model of the solar pressure so as to obtain best fit. The resulting model proved to be more accurate than the standard solar pressure model for GPS satellites (Fliegel et al., 1992). In a separate effort we developed from first principles a new solar pressure model for eclipsing GPS satellites. This model also represents a significant improvement over the standard model.