NTRIP Server follow survey-in status

[ereditsdani]

Hi!

I am using pygnssutils to start my NTRIP server from CLI. However I couldn't find a way to keep track of the status of the survey-in of the base station. I have seen that in PyGPSClient there is a way to keep track of that, and I wonder that is there any way to keep track of the survey-in status in pygnssutils as well?

Thanks you for your help!

[semuadmin]

Hi @ereditsdani

The pygnssutils gnssserver utility running in NTRIP Caster mode doesn't actually set or monitor the Survey-In (SVIN) status - it assumes the required base station mode (FIXED or SURVEY-IN) has already been successfully configured.

If you need guidance on how to configure the receiver initially, have a look at this example from the pyubx2 library:

https://github.com/semuconsulting/pyubx2/blob/master/examples/f9p_basestation.py

If you want to monitor the SURVEY-IN status while it's in progress, the relevant data is available via the UBX NAV-SVIN message - specifically the dur, valid and active attributes. You could, for example, use the pygnssutils gnssdump utililty to monitor SVIN status while the survey is in progress - e.g. something like this:

gnssdump --port /dev/ttyACM0 --baudrate 38400 --timeout 5 --quitonerror 1 --protfilter 2 --msgfilter NAV-SVIN --outputhandler "lambda msg: print(f'survey duration: {msg.dur}, valid?: {msg.valid}, active? {msg.active}')"

At the start, dur = 0, valid = 0 and active=1. Once running, you should see the dur value steadily increasing and, once successful, the valid flag will change to '1' and the active flag will change to '0'.

Alternatively, you could use something like the following Python code snippet (this is essentially what happens in PyGPSClient):

from serial import Serial
from pyubx2 import UBXReader

SURVEY_DURATION = 60  # required survey duration in seconds

stream = Serial('/dev/ttyACM0', 38400, timeout=5)
ubr = UBXReader(stream)
for raw, parsed in ubr:
   if parsed.identity == "NAV-SVIN":
      print(f"SVIN duration {parsed.dur} ({parsed.dur * 100/SURVEY_DURATION}%), valid? {parsed.valid}, active? {parsed.active}")

Hope this helps

[ereditsdani]

Thank you for your help, i have used the python code, and it worked like a charm! :)