NMEA messages

gistfile1.txt

GST - GNSS Pseudorange Error Statistics
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  $--GST,hhmmss.ss,x.x,x.x,x.x,x.x,x.x,x.x,x.x*hh<CR><LF>
  1. UTC time of the GGA or GNS fix associated with this sentence.
  2. RMS value of the standard deviation of the range inputs to
     the navigation process. Range inputs include pseudoranges &
     DGNSS corrections.
  3. Standard deviation of semi-major axis of error ellipse (meters)
  4. Standard deviation of semi-minor axis of error ellipse (meters)
  5. Orientation of semi-major axis of error ellipse (degrees from true north)
  6. Standard deviation of latitude error (meters)
  7. Standard deviation of longitude error (meters)
  8. Standard deviation of altitude error (meters)
  This message is used to support Receiver Autonomous Integrity
  Monitoring (RAIM). Pseudorange measurement error statistics can
  be translated in the position domain in order to give
  statistical measures of the quality of the position solution.
  If only GPS, GLONASS, etc. is used for the reported position
  solution, the talker ID is GP, GL, etc., and the error data
  pertains to the individual system. If satellites from multiple
  systems are used to obtain the reported position solution, the
  talker ID is GN and the errors pertain to the combined
  solution.
  
  GGA - Global Positioning System Fix Data, Time, Position and fix related data
  fora GPS receiver.
                                                        11
          1         2       3 4        5 6 7  8   9  10 |  12 13  14   15
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   $--GGA,hhmmss.ss,llll.ll,a,yyyyy.yy,a,x,xx,x.x,x.x,M,x.x,M,x.x,xxxx*hh<CR><LF>
  Field Number:
  1. Universal Time Coordinated (UTC)
  2. Latitude
  3. N or S (North or South)
  4. Longitude
  5. E or W (East or West)
  6. GPS Quality Indicator,
   `0 - fix not available`
   `1 - GPS fix`
   `2 - Differential GPS fix`
   `4 - RTK Fix coordinate (centimeter precision)`
   `5 - RTK Float (decimeter precision.`
  7. Number of satellites in view, 00 - 12
  8. Horizontal Dilution of precision
  9. Antenna Altitude above/below mean-sea-level (geoid)
  10. Units of antenna altitude, meters
  11. Geoidal separation, the difference between the WGS-84 earth ellipsoid and
      mean-sea-level (geoid), "-" means mean-sea-level below ellipsoid
  12. Units of geoidal separation, meters
  13. Age of differential GPS data, time in seconds since last SC104 type 1 or 9
      update, null field when DGPS is not used.
  14. Differential reference station ID, 0000-1023
  15. Checksum