Starting tests for the observation of GNSS-signals in view of the planned VLBI 2010 system. 

V. Tornatore1, and R. Haas2

	1Department of Hydraulics, Environmental, Road Infrastracture, Remote Sensing Engineering, Politecnico di Milano, Italy 
2Department of Radio and Space Science, Onsala Space Observatory, Chalmers University of Technology, Sweden

Oral presentation

One interesting aspect for the development of the VLBI2010 system would be to have the possibility to observe GNSS-signals. These observations are primarily aimed to verify and improve the array performance. Nevertheless it has to be taken into account the big advantage  that such observations could give since they could allow a direct link between kinematic reference frame of the natural radio sources used in geodetic VLBI and the dynamical reference frames of the artificial radio sources used in GNSS-systems. 
Two ideas will be discussed in this presentation, the observations of GNSS-signals with the future VLBI2010 telescopes and with small additional reference telescopes. We present some calculations for different GNSS-systems and various telescopes of different sizes and sensitivity in order to get a feeling for the to be expected signal strengths and how to treat these signals. We also address the question whether it could be possible to receive the strong GNSS L-band signals with the currently developed VLBI2010 broadband feed systems (designed for the frequency range of 2-14 GHz, i.e. S-band to Ku-band).