How does a software-defined GNSS receiver decode four systems?A software-defined GNSS receiver processes satellite signals entirely in code rather than dedicated hardware, decoding GPS, Galileo, GLONASS, and BeiDou simultaneously.What happened: The open-source GNSS-SDR project revealed a software-defined receiver that decodes signals from all four major global satellite navigation systems. Instead of relying on proprietary chips, it processes raw radio signals using flexible software. Finally, an answer for everyone who thought GPS was just magic blue dots falling from the sky.Key numbers: 4 global satellite constellations decoded (GPS, Galileo, GLONASS, BeiDou)1 software-defined radio architecture replacing dedicated hardware0 proprietary chips required for multi-constellation positioningWhy it matters: Software-defined receivers let developers rapidly iterate and customize positioning algorithms without waiting for new silicon. This flexibility accelerates research and makes multi-constellation access far cheaper.Bottom line: When your positioning hardware becomes software, the blue dot gets a lot more transparent.