An approach for estimating phase errors of a radio interferometer due to secondary waves

A phase error of a radio interferometer due to secondary waves is discussed statistically. As phases of secondary waves at each antenna may vary largely to a certain reference, those can be regarded as random variables. Therefore, these phases are assumed to have a uniform probability over a range of (0, 2 pi) and to be independent of each other at two antennas. Under this assumption, rms values of the phase error are calculated with a numerical technique. A case in which the secondary wave can be regarded as a plane wave is also discussed in comparison with the previous case.