  We present fits to determine Parton Distribution Functions using a diverse
set of measurements from the ATLAS experiment at the LHC, including inclusive
$W$ and $Z$ boson production, $t\bar{t}$ production, $W$+jets and $Z$+jets
production, inclusive jet production and direct photon production. These ATLAS
measurements are used in combination with deep-inelastic scattering data from
the electron-proton collider HERA. Particular attention is paid to the
correlation of systematic uncertainties within and between the various ATLAS
data sets and to the impact of model, theoretical and parameterisation
uncertainties.
