Recompilation of the Combined Extragalactic Radio Source Catalogues of IERS for Years from 1988 to 1992

Because of the importance of the combined catalogues of IERS to the implementation of a conventional celestial barycentric reference system and the insufficiency of the combined catalogues of the International Earth Rotation Service, the combined catalogues for years from 1988 to 1992 are recompiled in this paper. Methods are briefly discussed and comprehensive examinations are performed to the newly combined catalogues named as Cats. It is shown that the problems of inconsistent coordinate reference system in the IERS catalogues is overcome in the Cat series catalogues. The definition and maintenance of the frame orientation are also improved obviously. Comparisons show that the coordinates of some sources in IERS catalogues are shifted from the expected ones in the X-axis direction at about 0.6 mas in maximum. It is also points out that the orientation of the IERS combined catalogue in 1993 is in question.