NAV-PVT and NAV-SAT.md

Comparison of complete PVT solutions

• NMEA standard messages RMC+GGA+GSA+GSV+GBS
• PUBX format
• ublox Binary format
  • Possible alternative to NAV-SAT: NAV-SVINFO (same size)
  • Likely not needed as included in NAV-PVT

Right now we use RMC+GGA+GBS at high resolution, then GSA+GSV at lower resolution. Are there less expensive (in terms of bandwidth) options?

NMEA standard messages RMC+GGA+GSA+GSV+GBS

22:23:20  R -> NMEA GNRMC,  Size  70,  'Recommended Minimum Specific GNSS Data'
22:23:20  R -> NMEA GNGGA,  Size  79,  'Global Positioning System Fix Data'
22:23:20  R -> NMEA GNGSA,  Size  66,  'GNSS DOP and Active Satellites'
22:23:20  R -> NMEA GNGSA,  Size  44,  'GNSS DOP and Active Satellites'
22:23:20  R -> NMEA GNGSA,  Size  44,  'GNSS DOP and Active Satellites'
22:23:20  R -> NMEA GPGSV,  Size  72,  'GNSS Satellites in View'
22:23:20  R -> NMEA GPGSV,  Size  72,  'GNSS Satellites in View'
22:23:20  R -> NMEA GPGSV,  Size  72,  'GNSS Satellites in View'
22:23:20  R -> NMEA GPGSV,  Size  31,  'GNSS Satellites in View'
22:23:20  R -> NMEA GLGSV,  Size  66,  'GNSS Satellites in View'
22:23:20  R -> NMEA GLGSV,  Size  64,  'GNSS Satellites in View'
22:23:20  R -> NMEA GLGSV,  Size  53,  'GNSS Satellites in View'
22:23:20  R -> NMEA GAGSV,  Size  70,  'GNSS Satellites in View'
22:23:20  R -> NMEA GAGSV,  Size  70,  'GNSS Satellites in View'
22:23:20  R -> NMEA GNGBS,  Size  39,  'Satellite fault Detection'

Total of 912 bytes for a complete set

PUBX format

This format is interpreted by some libraries, such as NeoGPS, perhaps with the exception of PUBX03 as it's not listed

22:25:53  R -> NMEA PUBX00,  Size 110,  'Position Data'
22:25:53  R -> NMEA PUBX03,  Size 607,  'Satellite Data'
22:25:53  R -> NMEA PUBX04,  Size  68,  'Time of Day'

Total of 785 bytes for a complete set

ublox Binary format

This format is interpreted by some libraries, such as NeoGPS, with the exception of NAV-SAT not listed

22:14:15  R -> UBX NAV-PVT,  Size 100,  'Navigation PVT Solution'
22:14:15  R -> UBX NAV-SAT,  Size 388,  'Satellite Status and Information'

Total of 488 bytes for a complete set

• https://github.com/KumarRobotics/ublox/blob/master/ublox_msgs/msg/NavPVT.msg
• https://github.com/KumarRobotics/ublox/blob/master/ublox_msgs/msg/NavSAT.msg
• https://github.com/KumarRobotics/ublox/blob/master/ublox_msgs/msg/NavSAT_SV.msg

Possible alternative to NAV-SAT: NAV-SVINFO (same size)

This is listed in ublox support for NeoGPS

• https://github.com/KumarRobotics/ublox/blob/master/ublox_msgs/msg/NavSVINFO.msg
• https://github.com/KumarRobotics/ublox/blob/master/ublox_msgs/msg/NavSVINFO_SV.msg

Likely not needed as included in NAV-PVT

22:27:15  R -> UBX NAV-TIMEUTC,  Size  28,  'Universal Time Coordinated'

• https://github.com/KumarRobotics/ublox/blob/master/ublox_msgs/msg/NavTIMEUTC.msg