For many years, the United States' Global Positioning System and the Russian equivalent GLONASS were the only GNSS in operation. The playing field is changing and, in order to keep up with the evolving signals, frequencies and satellite constellations, major changes are required. The EU-funded PRECISIO (Professional receiver via software radio) project laid the groundwork for development of a software-defined receiver and associated components as an alternative to conventional hardware solutions. Work began by defining system and user requirements for a GNSS receiver based on software-defined radio, performing a stock taking exercise and gap analysis, and conducting a feasibility study. To optimise the system, project partners characterised prototype requirements, and then designed, developed and validated prototypes for the radio frequency (RF) front end, software-defined receiver and the antenna. This was mainly done through simulation, laboratory, controlled and field trials. The PRECISIO team developed a RF front end consisting of an analogue RF board and a digital board. The software-defined receiver was designed and applied to a field-programmable gate array-based architecture. A series of lessons learnt and future design and implementation recommendations were delivered for both components. In addition, a multi-frequency conical spiral antenna was built and a receiver validation tool was developed to help validate future systems. A detailed business plan and roadmap to commercially exploit the GNSS receiver was carried out. Presentations at conferences in Europe and the United States helped to raise the project's profile, communicate technical challenges and obstacles encountered, and disseminate findings to the GNSS community. PRECISIO successfully demonstrated the feasibility of a software-defined receiver for GNSS. When the components are fully exploited, the solution will provide high performance with configurability and flexibility to meet stringent demands of future professional markets and applications.
Global navigation satellite systems, software-defined receiver, PRECISIO, software radio, radio frequency front end