====== Protocol NMEA ======

NMEA = tbd...


===== Commandes =====

Source : https://cdn-shop.adafruit.com/datasheets/PMTK_A08.pdf


===== Trames de données =====

Trames type :
  * **$GPAAM** - Waypoint Arrival Alarm
  * **$GPALM** - GPS Almanac Data
  * **$GPAPA** - Autopilot Sentence "A"
  * **$GPAPB** - Autopilot Sentence "B"
  * **$GPASD** - Autopilot System Data
  * **$GPBEC** - Bearing & Distance to Waypoint, Dead Reckoning
  * **$GPBOD** - Bearing, Origin to Destination
  * **$GPBWC** - Bearing & Distance to Waypoint, Great Circle
  * **$GPBWR** - Bearing & Distance to Waypoint, Rhumb Line
  * **$GPBWW** - Bearing, Waypoint to Waypoint
  * **$GPDBT** - Depth Below Transducer
  * **$GPDCN** - Decca Position
  * **$GPDPT** - Depth
  * **$GPFSI** - Frequency Set Information
  * **$GPGGA** - Global Positioning System Fix Data
  * **$GPGLC** - Geographic Position, Loran-C
  * **$GPGLL** - Geographic Position, Latitude/Longitude
  * **$GPGSA** - GPS DOP and Active Satellites
  * **$GPGSV** - GPS Satellites in View
  * **$GPGXA** - TRANSIT Position
  * **$GPHDG** - Heading, Deviation & Variation
  * **$GPHDT** - Heading, True
  * **$GPHSC** - Heading Steering Command
  * **$GPLCD** - Loran-C Signal Data
  * **$GPMTA** - Air Temperature (to be phased out)
  * **$GPMTW** - Water Temperature
  * **$GPMWD** - Wind Direction
  * **$GPMWV** - Wind Speed and Angle
  * **$GPOLN** - Omega Lane Numbers
  * **$GPOSD** - Own Ship Data
  * **$GPR00** - Waypoint active route (not standard)
  * **$GPRMA** - Recommended Minimum Specific Loran-C Data
  * **$GPRMB** - Recommended Minimum Navigation Information
  * **$GPRMC** - Recommended Minimum Specific GPS/TRANSIT Data
  * **$GPROT** - Rate of Turn
  * **$GPRPM** - Revolutions
  * **$GPRSA** - Rudder Sensor Angle
  * **$GPRSD** - RADAR System Data
  * **$GPRTE** - Routes
  * **$GPSFI** - Scanning Frequency Information
  * **$GPSTN** - Multiple Data ID
  * **$GPTRF** - Transit Fix Data
  * **$GPTTM** - Tracked Target Message
  * **$GPVBW** - Dual Ground/Water Speed
  * **$GPVDR** - Set and Drift
  * **$GPVHW** - Water Speed and Heading
  * **$GPVLW** - Distance Traveled through the Water
  * **$GPVPW** - Speed, Measured Parallel to Wind
  * **$GPVTG** - Track Made Good and Ground Speed
  * **$GPWCV** - Waypoint Closure Velocity
  * **$GPWNC** - Distance, Waypoint to Waypoint
  * **$GPWPL** - Waypoint Location
  * **$GPXDR** - Transducer Measurements
  * **$GPXTE** - Cross-Track Error, Measured
  * **$GPXTR** - Cross-Track Error, Dead Reckoning
  * **$GPZDA** - Time & Date
  * **$GPZFO** - UTC & Time from Origin Waypoint
  * **$GPZTG** - UTC & Time to Destination Waypoint  

Sources :  
http://aprs.gids.nl/nmea/#latlong  
http://www.gpsinformation.org/dale/nmea.htm#nmea