Talker ID and GNSS constellation

Hi all,

me again :slight_smile:
Just a question :
From what I read online, the Talker ID is here to help and differentiate from the NMEA trame which constallation was used to generate the Trame NMEA


But in my M2, in the RTK settings, I can select all , and can not uncheck GPS, which is look normal to me :

My question is, if I use GP or GN as talker ID, but I check GPS and Galileo in RTK settings, are the info from Galielo taken in consideration and computed to generate the NMEA or not at all ?

The talker ID for Galileo should be GA, but it is not possible to select it in the Position Output.

Any thought ? :thinking:

We just tested and removed some GNSS, and the fix was longer with RS2 and M2 multiband,

As soon as I put back the other get the the fix back pretty quickly.

Early legacy systems used to use talker code “GP”

The talker code was originally intended for the NMEA bus of a ship. Because on the same NMEA bus you would have engine, hvac, cargo data and more all sharing the same data bus.

Dependant on the receiving hardware it can be picky about the talker code. Legacy systems parser code usually rejects GNGGA vs GPGGA data because it cannot decipher the GN.

Newer parsers look for GN not GP, some ignore the talker code regardless.

Talker code or ID has nothing to do with the individual constellations. Its to identify the data is coming from a gps or a gnss on a common nmea data bus.


Ok, so when I select the GNSS galilelo it is taken in consideration for the computing right ?

Galileo is the constellation for computing a position.

The talker code is just two letters that say what type of hardware the data is coming from. They have no effect on the calculation at all.

The next three letters after the talker code signify the sentence of data being transmitted.

GGA for example would contain position and basic satellite and fix information.

VTG would contain course over ground, heading and motion information.


Thank you I consider the topic as closed

Hi there,

@PotatoFarmer comments hit the bull’s-eye, so I have nothing to add :slight_smile:

Just want to confirm his words and share this article on the different types of NMEA messages.

Thank you!

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