GPS / GNSS (Marine)
GPS (Global Positioning System) — more generally GNSS (Global Navigation Satellite System), encompassing the US GPS, Europe's Galileo, Russia's GLONASS and China's BeiDou — provides a ship with its precise position, course over ground and speed by receiving timing signals from a constellation of satellites. It has become the primary source of position for navigation worldwide.
GPS/GNSS underpins nearly every modern navigation and safety system: it feeds the ECDIS (placing the ship on the electronic chart), AIS (broadcasting position), radar, autopilot and voyage recording. Its accuracy transformed navigation from an art of estimation into precise, continuous positioning. However, reliance on it creates a vulnerability — GNSS can be jammed or spoofed (deliberately disrupted or falsified), which has become a real navigational risk in some regions, so prudent navigators retain the ability to cross-check position by other means (radar, visual, and traditional techniques like dead reckoning). GPS/GNSS is foundational to contemporary ship navigation and to the wider tracking of vessels, and its integrity is an increasing safety and security concern. It is central to how ships know where they are.
GPS turned navigation from educated estimation into precise, continuous positioning, and it now feeds ECDIS, AIS, radar and autopilot alike — the backbone of the modern bridge. But that dependence is also a weakness: jamming and spoofing are real and growing risks, which is why prudent navigators still cross-check position and keep traditional skills. Knowing where the ship is starts with GNSS.
What is the difference between GPS and GNSS?
GPS is the US satellite system; GNSS is the general term covering all such systems — GPS, Galileo, GLONASS and BeiDou.
What is GNSS spoofing?
Deliberately transmitting false satellite signals to give a ship an incorrect position — a growing navigational risk that makes cross-checking essential.