Multi-Constellation GNSS Receiver

A GNSS receiver that tracks two or more satellite systems at once, GPS, Galileo, GLONASS, and BeiDou, plus regional systems, to improve availability, accuracy, and resilience. Combining constellations gives more satellites in view, better geometry (lower DOP) in urban or fjord environments, and a degree of protection against jamming or spoofing affecting one system. Multi-frequency tracking (for example L1/L5, E1/E5) removes most ionospheric error and aids spoofing detection. IMO Resolution A.1046(27) sets GNSS shipborne receiver performance standards; modern units meet the worldwide radionavigation system requirements.