PointPerfect MQTT Correction

[drodriguez-dlc]

I'm using example/client.py with pygnsutils GNSSSocketServer and trying to implement GNSSMQTTClient. I start the server with this command
gnssserver --inport /dev/ttyGPS --baudrate 115200 --hostip 0.0.0.0 --outport 50011

Then start the MQTT connection
gnssmqttclient -C c3938143-fe52-xxxx-b2da-xxxxxxxxxxxx -S pp.services.u-blox.com -P 8883 -R us --output /dev/ttyGPS
I can see my device connected on PointPerfect(PP), but I'm unsure of how to actually send the correction data to my ZED-F9P.

Utilizing pygpsclient UI, I can connect to my server at 0.0.0.0:50011 and then connect to my MQTT broker to retrieve the correction data and I can eventually get an RTK fix.

How can I replicate this pygpsclient functionality using the example client, gnssserver, and gnssmqttclient?
Would GNSSStreamer be better suited for this task?

[semuadmin]

Hi @drodriguez-dlc

Unfortunately you can't use gnssmqttclient to output directly to a serial device (e.g. /dev/ttyGPS) - you need to open it as a writeable stream first. The gnssmqttclient --output parameter accepts any of the following writeable output classes:

• serial stream (Serial)
• binary file stream (BufferedWriter)
• text file stream (TextIOWrapper)
• queue (Queue)
• socket (Socket)

The way this works 'under the covers' in PyGPSClient is that it writes the output from gnssmqttclient to a queue, and a separate threaded process reads this queue and sends the data to the receiver.

The rtk_example.py does something similar but for NTRIP clients rather than SPARTN, but you could adapt it quite easily to use GNSSMQTTClient rather than GNSSNTRIPClient. If you need any guidance doing this, get back to me.

[drodriguez-dlc]

Very much appreciate the quick reply! I'll give this a shot this evening.

[drodriguez-dlc]

I was able to modify rtk_exmaple.py to output its data to the send_queue. Thanks again for the help!
I do have one more question that is not related to the original question. Do you prefer a new thread for that?

[semuadmin]

If it's an unrelated subject, create a new thread. Thanks. Could I ask you to mark this thread as 'Answered' if you're happy with the resolution.