NMEA 0183 (.nmea)
NMEA 0183 is not really a file format — it is the stream of text sentences a GPS receiver speaks over a serial line. Saved to disk, that stream becomes a track log anything can read.
At a glance
| Extension | .nmea |
| Encoding | text |
| Invented | 1983 |
| By | National Marine Electronics Association (NMEA) |
| Current version | 4.30, published December 2023 |
History
The National Marine Electronics Association defined NMEA 0183 in 1983, replacing its earlier NMEA 0180 and 0182 standards. It has been revised many times since; version 4.30 was published in December 2023. NMEA 2000 has largely taken over in leisure boating, but NMEA 0183 remains the norm in commercial shipping and is still what a bare GPS chip emits.
Where it is used
Marine GPS units, chartplotters, AIS transponders, USB GPS receivers and basic data loggers all speak NMEA 0183. Almost any software that talks to a GPS receiver directly — navigation programs, aviation tools, radiosonde trackers — parses it.
Structure
NMEA 0183 is plain printable ASCII carried over a serial line, classically at 8-N-1 and 4800 baud (38400 for the high-speed AIS variant). Each sentence starts with $ or !, then a two-character talker ID and a three-character sentence type, then comma-separated fields, then an asterisk and a two-digit hexadecimal checksum, and ends with carriage return and line feed; a sentence is at most 82 characters. For GPS the sentences that matter are GGA (fix, time and altitude), RMC (the recommended minimum of position, speed and date), GSA (fix mode and dilution of precision) and GSV (satellites in view).
How widespread
NMEA 0183 is the lowest common denominator of satellite navigation: no route structure, no metadata, no nesting — just position fixes over time. That makes it universally readable and a poor choice for anything you want to plan rather than record.
RouteConverter support
| Reads | NMEA 0183 Sentences |
| Writes | NMEA 0183 Sentences |