1. Parametric Study of Solar Radiation Pressure Model Applying to Navigation Satellite Orbit Determination for Long Arc

The precision of broadcast ephemeris of navigation satellite is one of the important factors, which determines the performance indicator of navigation satellite system. However, the result of precise orbit determination and orbit prediction affected the precision of broadcast ephemeris. It’s a very complex task to calculate the precise orbit of satellite. The in-orbit satellite is effected by several kinds of perturbations, that are Earth’s non-spherical gravitation, Sun and Moon gravitation, solar radiation pressure (SRP), tidal acceleration and other little perturbing acceleration. Compared with the other pressure, SRP is the most important error source for medium-earth-orbit satellites. On the basis of engineering parameter and attitude control modes of a certain navigation satellite, this paper had constructed the composite SRP model including direct SRP, thermal radiation pressure (TRP), Earth radiation pressure (ERP). The influence of SRP model parameters had been analyzed in precise orbit determination by long arc orbit calculation. According to the analyzed result, the adjust strategy of the parameters of SRP model had been given for long arc orbit determination, thus the result of orbit determination could be improved further.