ADIBEAM: Design and experimental validation of a robust beamforming platform for Galileo reference ground stations

The increase in navigation accuracy demanded by EGNOS and Galileo and their future evolution encourages the study and design of advance receiver architectures. In that direction, the ADIBEAM project focuses on the design of high accuracy ground stations, specifically GNSS Reference Stations, in order to improve its robustness in front of multipath and interference errors with the goal of achieving centimeter level tracking accuracy. The adoption of antenna arrays and digital beamforming at the ground reference station receivers is one of the most promising approaches to cope with errors induced by multipath and interference. This paper proposes an innovative design of a ground based tracking station. In particular, the architecture proposed is based on the use of an antenna array and digital beamforming techniques, considering both adaptive and deterministic methods. The work carried out here considers the ground based tracking system, including the characterization of the system components (antennas, RF chains, calibration techniques, GNSS software receiver and digital beamforming), and the development of a software based experimentation platform representative of the proposed design for a hardware prototype. The sensitivity to perturbations and the extreme difficulty to perfectly control and calibrate all the components of the system, especially regarding the antenna array implementation, requires that the proposed design take into consideration not only the benefits of the possible solutions but also their feasibility for a real implementation. In summary, this paper will present the design proposed and the Experimentation Platform used for its validation.