Confusion in interferometer observations

The confusion probability distribution in interferometer observations is derived. It is shown that the form of the distribution depends on the correlation between fringe visibilities V and flux densities S of radio sources. Because the V-S correlation depends on the universe model, the evolution of radio source dimensions, and the evolution of the radio luminosity function, the statistical VLBI observations give a new cosmological test to analyse different universe models and evolution models. An expression for the variance of the confusion distribution is obtained. It is shown that the confusion variance in VLBI observations is much less than that in observations with a single radio telescope.