The following thesis dissertation has been carried out at the Beijing's University of Aeronautics and Astronautics (Beihang University), with the aid of the SNARS Research Group and of professors Falin Wu and Fabio Dovis. The aim of this thesis project is to investigate techniques capable to improve the performances of a tightly coupled SINS/GNSS Integrated System with the assistance of a Radial Basis Function Neural Network. Indeed, precise and accurate navigation is nowadays required also for civil applications. The combination of a INS (Inertial Navigation System) and of a GNSS (Global Navigation Satellite System) is already able to improve the performances of such an integrated navigation system.