GPS satellites: Radiation pressure, attitude and resonance Original Research Article

At the altitude of the CPS satellites the most important non-gravitational perturbation is caused by the solar radiation pressure acting on the satellite body and its solar panels. The development of high-fidelity radiation pressure models may be motivated by the following observation: The GPS satellites are orbiting in a 2:1-commensurability with the Earthʹs rotation which causes resonance. The expected sensitivity to specific coefficients of the geopotential is, however, significantly reduced by strong correlations of these parameters with radiation pressure parameters. Sophisticated radiation pressure models rely on a precise knowledge of the satelliteʹs attitude which does not only affects the location of the antenna phase center or the phase windup of the signal carrier but, through radiation pressure, also the orbital dynamics. PRN 23, whose attitudinal behaviour was modified early in 2002 is an interesting case. Due to this change an impressive improvement in the orbit quality could be achieved.