Some studies have suggested the importance of modelling the Earth radiation that reaches GPS satellites, an effect that is not currently included by most of the Analysis Centres that contribute to the computation of the IGS (International GNSS Service) Final Orbits. It is also thought that Earth radiation could be partially responsible for the observed bias between SLR (Satellite Laser Ranging) and GPS (Global Positioning System) measurements, known as the GPS – SLR orbit anomaly. Furthermore this bias sets the actual limits for the accuracy that can be achieved in the computation of the GPS orbits. In this thesis several models of different complexity are developed, in particular models for Earth radiation that reaches the satellites and models of the satellite structure that interact with the radiation coming from the Earth. The complete development of these models is given in the thesis together with deep analysis about the differences of the models. For the interested person, the programs for the computation of the acceleration due to Earth radiation pressure are also provided. The computed acceleration is also introduced in the computation of GPS orbits. First the perturbing acceleration is used for a very simple study case where a general understanding of the effect of Earth radiation on the orbits can be acquired. Second the perturbing acceleration is introduced in the Bernese GPS Software for the computation of GPS orbits as done by CODE (Center for Orbit Determination in Europe). The effects on the orbits are studied per revolution and per year. The computed orbits using the Bernese GPS Software are compared with SLR measurements, to have an external validation. Doing that a reduction of the GPS – SLR orbit anomaly is obtained, leading to a potential subcentimeter accuracy of the orbits. Finally as Earth radiation and satellite models of different complexity were tested, it is possible to give a recommendation of the key factors for an adequate but simple modelling of Earth radiation pressure for GPS satellites.      «

Some studies have suggested the importance of modelling the Earth radiation that reaches GPS satellites, an effect that is not currently included by most of the Analysis Centres that contribute to the computation of the IGS (International GNSS Service) Final Orbits. It is also thought that Earth radiation could be partially responsible for the observed bias between SLR (Satellite Laser Ranging) and GPS (Global Positioning System) measurements, known as the GPS – SLR orbit anomaly. Fu...     »