  In this study, we compared results of determination of the orientation angles
between celestial reference frames realized by radio source position catalogues
using three methods of accounting for correlation information: using the
position errors only, using additionally the correlations be-tween the right
ascension and declination (RA/DE correlations) reported in radio source
position catalogues published in the IERS format, and using the full covariance
matrix. The computations were performed with nine catalogues computed at eight
analysis centres. Our analysis has shown that using the RA/DE correlations only
slightly influences the computed rotational angles, whereas using the full
correlation matrices leads to substantial change in the orientation parameters
be-tween the compared catalogues.
