NMEA (National Marine Electronics Association) is the standardized communication protocol used by virtually all GNSS receivers to output position, velocity, time, and status information to connected devices and applications. Originally developed for marine electronics in the 1980s, the NMEA 0183 protocol has become the universal interface standard for GPS and GNSS equipment across all industries, enabling interoperability between receivers, mapping software, data loggers, and navigation systems from different manufacturers.

The NMEA 0183 protocol uses simple ASCII text strings called sentences, each beginning with a dollar sign and a talker/message type identifier. Common sentence types include GGA (position fix data including coordinates, quality, and satellite count), RMC (recommended minimum data for navigation), GSA (satellite status and DOP values), GSV (satellites in view with signal strength), and VTG (velocity and track information). Each sentence contains comma-separated data fields followed by a checksum for error detection, making the format human-readable and easy to parse with simple software.

Several characteristics of NMEA 0183 reflect its origins and widespread adoption. The serial communication architecture assumes point-to-point connections between talker (transmitting device) and listener (receiving device). Data rates are relatively low (typically 4800 baud originally, though modern implementations use faster rates). The ASCII format prioritizes simplicity and debugging ease over bandwidth efficiency. These characteristics made NMEA 0183 practical for 1980s marine electronics and have enabled its continued use across decades of technological evolution.

While NMEA 0183 remains dominant for basic GNSS interfacing, limitations exist for advanced applications. The protocol lacks support for high-bandwidth data like raw measurements or RTK corrections, these require proprietary binary protocols or RTCM standards. Newer NMEA protocols address some limitations: NMEA 2000 uses CAN bus for higher-speed multi-device networks, and NMEA OneNet employs Ethernet for applications requiring high bandwidth. For precision positioning applications, NMEA output provides convenient access to position solutions and quality indicators, while correction data and raw observations typically use dedicated protocols like RTCM.