Simulations for different antenna velocities in a VLBI network
S. Garcia-Espada1,2, R.Haas2 and F. Colomer2

1National Geographic Institute, Spain
2Department of Radio and Space Science, Onsala Space Observatory, Chalmers University of Technology,  Sweden

Poster

During 2008 the new 40-m radiotelescope at Yebes (Ys) started to participate in IVS geodetic VLBI sessions. It was necessary to decide the most suitable antenna velocity in azimuth and elevation for the site itself and the network performance. To evaluate the impact of different telescope velocities on geodetic results we used the scheduling software SKED and created schedules with different antenna velocities for Ys. We focussed on the two sessions EURO94 and R1331 and analyzed the schedules with SKED itself, and with the VLBI analysis software SOLVE, both with and without introducing simulated atmosphere and clock contributions. We found that the schedules with a fast Ys antenna (3 º/s in az. and el.) give slightly better results than the ones with a slow Ys antenna (1 º/s in az. and el.). For the studied EURO session the standard deviation of the estimated topocentric U-component for Yebes is similar for a fast and slow antenna. For the R1-experiment the standard deviations of all three topocentric station components improve for a fast antenna. The SKED-only results appear to be too optimistic, while the SOLVE results show more realistic estimates for the UEN components and sigmas.  We found no significant difference in the UEN sigmas with or without introducing simulated atmospheric and clock contributions, although the WRMS fit becomes slightly worse.