Estimating Subdaily Earth Rotation Parameters using Galileo
Hugentobler, U.; Heinze, M.; Svehla, D.
Technische Universität München

GPS satellites orbit the Earth in nearly exactly half a sidereal day. Galileo (as well as GLONASS) satellites have a revolution period that differs significantly from this 2:1-commensurability with Earth rotation. As one consequence Galileo satellites require less frequent maneuvers than GPS satellites that are repositioned about once per year. Subdaily polar motion and length of day contain periods close to 24 hours and 12 hours that are mainly caused by ocean tides. Orbit perturbations, e.g., due to solar radiation pressure, have typical periods of the revolution time and thus affect the estimation of subdaily Earth rotation parameters with GPS observations in the diurnal and semi-diurnal band. The orbital period for Galileo satellites is far enough from the semi-diurnal frequency band of Earth rotation such that the estimation of subdaily Earth rotation parameters should be less affected by orbit modelling deficiencies. Simulations show the impact of the inclusion of tracking data from other GNSS constellations than GPS on the estimation of subdaily Earth rotation parameters.