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The VLBI USNO 2016A (U16A) solution is part of a work-in-progress effort byUSNO towards the preparation of the ICRF3. Most of the astrometric improvementwith respect to the ICRF2 is due to the re-observation of the VCS sources. Ourobjective in this paper is to assess U16A's astrometry. A comparison with ICRF2shows statistically significant offsets of size 0.1 mas between the twosolutions. While Gaia DR1 positions are not precise enough to resolve theseoffsets, they are found to be significantly closer to U16A than ICRF2. Inparticular, the trend for typically larger errors for Southern sources in VLBIsolutions are decreased in U16A. Overall, the VLBI-Gaia offsets are reduced by21%. The U16A list includes 718 sources not previously included in ICRF2.Twenty of those new sources have statistically significant radio-opticaloffsets. In two-thirds of the cases, these offsets can be explained fromPanSTARRS images.

Towards the ICRF3: astrometric comparison of the USNO 2016A VLBI solution with ICRF2 and Gaia DR1