This proposal has been prepared in response to the EUMETSAT ITT on “Scientific Service for Fiducial Reference Measurements for Copernicus Aerosol Product Cal/Val Activities”. For that purpose, we have developed an extensive analysis of the current operational retrievals and research studies, as well as the ground-based networks that contribute with aerosol remote sensing observations that are suitable for aerosol cal-val purposes, mainly using photometer and lidar. This analysis illustrates our understanding of the objectives and purpose of the Service. All this in hand, we describe the approach to each of the five activities that the Service must include. In them we accommodate both the operational needs of the cal-val activity, as well as the research efforts for improvement and new developments of retrieval algorithms, uncertainty estimates and quality control. We have also followed the principle of avoiding duplication of existing infrastructures; indeed we propose to build on them, as it is the case of the databases of operational networks (AERONET, ACTRIS, SKYNET) or the DIVA platform for algorithm testing developed in the frame of an ESA funded project. We can therefore concentrate on novel algorithm development and testing, and foresee the development of dedicated or tailored products for specific cal-val exercises, including data from campaigns of opportunity. The service will create a dedicated fiducial reference measurement database for aerosol cal-val, and will provide it with an operational processing scheme using GRASP and other algorithms for advanced aerosol characterization.