An open-source Global Navigation Satellite Systems software-defined receiver
The free and open-source software tool that is reshaping R&D in satellite-based navigation receivers.
The swiftly evolving landscape of GNSS signals and their upgrades demands rapid prototyping tools to explore receivers’ full capability, including radically new uses of those signals. That flexibility is hard to find in today’s GNSS receiver technology, mainly driven by application-specific integrated circuits (ASIC) and system-on-chip (SoC) implementations with high development costs and a very limited degree of reconfigurability, thus hampering experimentation and fair trials of new approaches. Intending to effectively perform R&D on the core engine of a GNSS receiver, CTTC developed GNSS-SDR, a software-defined receiver that can replace ASIC functionality and allows exploring new directions in receiver design with a drastically reduced entrance barrier.
GNSS-SDR is a software package released under the GNU General Public License v3.0.
It provides a framework for the whole signal processing chain inside a GNSS receiver, from raw signal samples coming from an analog-to-digital converter up to the computation of the Position-Velocity-Time solution, including the generation of “GNSS products” such as code and phase observables.
The software is capable to work with raw data files or, if there is computational power enough, in real-time with suitable radiofrequency front-ends. It is designed to facilitate the inclusion of new signal processing techniques, offering an easy way to measure their impact on the overall receiver performance.
Today, GNSS-SDR is a popular tool among GNSS researchers, developers, and hobbyists around the world, constituting a steadily growing user community that continually provides feedback and contributes to software improvement.
The inherent flexibility of the software-defined radio approach has allowed reaching relevant research milestones over time. In 2013, The European Space Agency acknowledged CTTC as one of the first 50 users of the Galileo system Worldwide, showing the competitiveness of this technology. Since then, GNSS-SDR has shown its applicability in many disparate fields, such as precision agriculture or spaceborne receivers, or in radically new approaches as the virtualized GNSS receiver in the cloud.
CTTC researchers are continually evolving the software and making it useful for new scenarios.