SDR GNSS receivers: A comparative overview of different approaches

Co-existence of different constellations for Global Navigation Satellite Systems (GNSS) provides new opportunities to improve the services offered to the users, but also poses new challenges and increased complexity in receiver design. To ensure flexibility and dynamic re-configuration, Software Defined Radio (SDR) receivers seem to be the natural solution, both for the research and industrial communities. This paper wants to provide an overview of the solutions proposed until now, trying to highlight what the trend is in SDR GNSS receiver development, and to what extent currently proposed SDR approaches are able to replace traditional hardware-based design.