What is NMEA?
A. The acronym stands for “National Marine Electronics Association” and is again an industry association that sets data transmission standards. In this case, the real name is NMEA 180. It is a set of standard messages defining the possible outputs of a GPS receiver. There are several “sentences” available; each of which has some unique data associated with them. They are all in ASCII format and are in the form of comma delimited strings. String lengths vary from 30 to 100 characters and are output at the interval chosen – again usually once per second. The most common string (or sentence) is called the “GGA” string. It contains the Time of the Fix, Latitude, Longitude, Height, Number of Satellites used in the fix, DOP, Differential Status, and the Age of the Correction (RTCM). Others have Speed, Track, Date, etc. NMEA is available in virtually all GPS receivers and is the most commonly used data output format. It is also the format used in most software packages that interface to a GPS
