GST - GNSS Pseudorange Error Statistics

       1         2   3   4   5   6   7   8
       |         |   |   |   |   |   |   |
$--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 preudoranges & 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.