Appendix A - NMEA messages
APA
Autopilot Sentence “A” contains navigation receiver warning flag status,
crosstrackerror, Waypoint arrival status and initial bearing from origin Waypoint to the
destination Waypoint for the active navigation leg of the journey.
APB
Autopilot message contains all of the above plus: heading to steer toward
destination, bearing from the present position to the destination (magnetic or true).
GGA
GPS position, time, fix quality, number of satellites used, height of antenna, HDOP
(Horizontal Dilution of Precision), differential reference information and age.
GSA
GPS receiver operating mode, satellites used in the navigation solution reported
by the $— GGA sentence.
GSV
Number of satellites in view, satellite numbers, elevation, azimuth, and SNR value.
RMB
Data status, Cross Track Error, direction to steer, origin, destination Waypoint,
Waypoint location, bearing to destination and velocity toward the destination.
RMC
Time, Latitude, Longitude, Speed Over Ground, Course Over Ground and date.
For information about the NMEA format specifications: www.nmea.org.