Clock strategy experimentation with GIOVE clocks

GIOVE satellites broadcast currently a clock model in the navigation message which targets a maximum one day validity time. The associated accuracy is limited by the inadequacy of the model to the clock drift for the RAFS and to the presence of harmonics in the phase. The perform ance maybe increased by optimizing the fitting intervals and including an additional harmonic term in the clock model estimation. The associated stochastic model to the clock prediction is as well limited by the harmonic inclusion. A meaningful stochastic model associated to the prediction can be defined in case the harmonic is taken into account in the estimation.