SimpleRTK2B + Wi-Fi NTRIP Master + Raspberry Pi adapter: How to retrieve corrected NMEA data?

Q&A forumCategory: QuestionsSimpleRTK2B + Wi-Fi NTRIP Master + Raspberry Pi adapter: How to retrieve corrected NMEA data?
maximilian.torggler asked 3 months ago

we are currently trying to retrieve the same data as u-center is displaying, using a RaspberryPi via serial communication.
So far we were able to retrieve data like mentioned in the tutorial (, but we weren’t able to access the data as it is displayed in u-center.
Red: The actual data we are receiving
Blue: The data we would like to receive

Is this because here the data without NTRIP correction is transmitted on the UART1 serial port or is it somehow related to the NMEA protocol? If so, could we somehow change that behaviour? Or would it be able to output the data in other formats?
Does anyone know how we could proceed? Any hints would be greatly appreciated!

Ardusimple Staff replied 3 months ago

By default, the data received by RPi should be the one from GPS UART1, this means NMEA at 38’400bps.

1 Answers
Best Answer
clive1 answered 3 months ago

NMEA returns data in a degrees/minutes form DDDMM.mmmmm you’ll need to convert to decimal degrees if that’s what you want. You’ll also need to unpack the NMEA sentences to get the RTK FIXED/FLOAT fix type.
The $GPTXT txbuf alloc warning indicates you are outputting too much data to a slower interface. Turn off interfaces you are not using, or limit the messages output to them.

maximilian.torggler replied 3 months ago

Well, that makes sense. Converting those values does the trick. Thanks a lot!
By unpacking you mean parsing? Do you know which sentence includes the RTK FIXED/FLOAT fix type?

maximilian.torggler replied 3 months ago

Nevermind, GNGGA contains everything we need.