In Kurtenbach (2011) and Kurtenbach et al. (2012) an approach has beenintroduced that allows to calculate daily gravity field solutions from GRACE datawithin the framework of a Kalman filter and smoother estimation. The method uti-lizes spatial and temporal correlations of the expected gravity field signal derivedfrom geophysical models in addition to the daily observations, thus effectively con-straining the spatial and temporal evolution of the GRACE solution. Here, we offeran extended validation of these daily solutions by comparing the derived mass variations to vertical displacements at various permanent GPS stations. The comparison confirms the conclusion that the daily solutions contain significant high-frequent temporal gravity field information, especially in higher latitudes. The final version is available at https://link.springer.com/chapter/10.1007%2F978-3-642-32135-1_6.