The H2020 project AUDITOR of the European Union started on January 1st 2016, with the participation of several European institutions and universities. The goal of the project is the implementation of a novel precise positioning technique, based on augmentation data in a customized GNSS receiver. Therefore more sophisticated ionospheric models have to be developed and implemented to increase the accuracy in real-time at the user side. Since the service should be available for the public, we use public data from GNSS networks (e.g. IGS, EUREF). The contributions of DGFI-TUM and UPC are focusing on the development of high accuracy GNSS algorithms to provide enhanced ionospheric corrections. This includes two major issues: