Piksi® Multi (firmware v1.1 and newer) and Duro support following NMEA 0183 messages: GGA, GLL, GSA, GSV, HDT, RMC, VTG and ZDA. Starting with firmware v2.3, the GST message is also available.
NMEA messages are available on both UART ports, USB (Piksi Multi only) and Ethernet port. Messages conform to NMEA 0183 standard version 2.3. Official NMEA protocol specification can be found on the NMEA organization site: https://www.nmea.org/
Enabling NMEA Messages
To enable NMEA messages change desired port mode to NMEA OUT using Swift Console (Settings tab -> desired interface port group -> mode). To make change permanent click Save to Device button on Swift Console settings tab.
Fig. 1. Example of NMEA Messages Enabled on UART0
- Do not change port mode on the port you’re using to communicate with the Swift Console. Changing mode is instantaneous and as Swift Console does not support NMEA protocol you’ll not be able to save settings or make other changes. Always use another port/interface to change the port mode.
- Port in NMEA mode only outputs messages. Any input is ignored.
Selecting NMEA Message Rates
Use Swift Console Settings tab to change NMEA messages rates or to disable them (Settings tab -> nmea section). Message rates are common for output on all interfaces.
Fig. 2. Piksi Multi NMEA Settings Group
Number in the right column is used to specify the message output rate. Set it to zero to disable message output. Rate value is a position solution frequency (solution group -> soln_freq) divider.
New settings starting from firmware v3.0:
- cog output min speed controls when Course Over Ground (COG) value is being output. Set this to zero to always output the COG value.
- cog update min speed sets the minimum speed required to update COG value.
- With solution rate at 10 Hz and with GGA message rate set to 1 the GGA message will be output at 10/1 = 10 Hz rate.
- With solution rate at 10 Hz and with ZDA message rate set to 10 the ZDA message will be output at 10/10 = 1 Hz rate.
- On firmware versions 2.4 and older Course Over Ground (COG) in the VTG and RMC message is not populated when the speed is below 0.1 m/s.