  Position resolution is a key property of the innermost layer of the upgraded
ATLAS and CMS pixel detectors for determining track reconstruction and flavor
tagging performance. The 11 GeV electron beam at the SLAC End Station A was
used to measure the position resolution of RD53A modules with a $50\times50$
and a $25\times100\ \mu$m$^2$ pitch. Tracks are reconstructed from hits on
telescope planes using the EUTelescope package. The position resolution is
extracted by comparing the extrapolated track and the hit position on the RD53A
modules, correcting for the tracking resolution. 10.9 and 6.8 $\mu$m resolution
can be achieved for the 50 and 25 $\mu$m directions, respectively, with a 13
degree tilt.
