NMEA (National Marine Electronics Association) is not a GPS system itself, but rather a set of communication standards used in marine electronics devices to share information, including GPS location data.
The NMEA standards define the way in which different marine electronics devices communicate with each other over a network, and include protocols for sending and receiving data related to GPS, sonar, weather, and other types of information.
GPS (Global Positioning System), on the other hand, is a satellite-based navigation system that provides accurate location and time information to GPS receivers anywhere on or near the Earth. GPS data can be transmitted between devices using the NMEA 0183 or NMEA 2000 protocols.
So while NMEA standards do facilitate the transmission of GPS location data between devices, they are not GPS systems themselves.
