EDGAR (EGNSS DFMC for GBAS bAsed opeRations) Project aims at contributing towards the development of an improved, more liable, and accurate GBAS solution that responds, on the one hand, to the increasing demand for enhanced approach and all-weather operations in the ever-growing volume of air operations; and on the other hand, to sustainability requirements towards the compliance with EU Green Deal objectives. Being GBAS an enabler of enhance approach and optimised descent operations permits the reduction of noise footprints, fuel consumption and emissions, thus contributing to greener flights. Moreover, this project pursues to contribute to the goal of an early Dual-Frequency Multi-Constellation, or DFMC, GBAS adoption that allows facing ILS CAT III rationalization thanks to the increased robustness and thus rendering benefits to the aviation community. Therefore, the application of GBAS alongside EGNSS will technically improve the current system and will have a positive impact on the economy and society. Hence, the main objectives of this proposal are: to further develop and validate the GBAS DFMC solution so as to modernise and improve air operations, with emphasis on providing safety, availability, and robustness in all situations, including during challenging to ionospheric conditions; to analyse the distinguishing features of Single-Frequency Multi-Constellation, or SFMC, GBAS brought by the addition of Galileo; and to facilitate CAT II service to GAST C airborne users based on a GAST D ground station with EGNSS integration (GAST C and D correspond to standardized single-frequency single-constellation equipment able to provide CAT I and III performances respectively).