The National Marine Electronics Association (NMEA) is a national standards development association for marine electronics in the United States. There are several data sets developed by NMEA for marine communications. NMEA 0183 (IEC 61162-1) is probably the best known NMEA communication standard, which is also used in the GPS system and other satellite navigation systems. GPS devices, personal computers or marine navigation devices can display the NMEA data on their displays with appropriate navigation programs and navigate with it.
The NMEA standard NMEA 0180, the first version of which was published in 1980, is used to transmit position data. These can be received and evaluated by stationary and mobile receiving stations. The data rate at that time was 1,200 baud; a few years later it was increased to 4,800 baud in NMEA standard 0182. The best known and still used standard is NMEA 0183, which introduced a clear separation between transmitting and receiving devices.
The NMEA data set uses the ASCII character set and includes the Coordinated Universal Time (UTC) time information in hours (h), minutes (m), seconds (s) and tenths of a second, the date information, the position information in longitude and latitude and the speed and direction (degrees). A checksum is formed over the complete data set and appended to it.
There are more recent NMEA standards than NMEA 0183, but these are only implemented in a few devices.