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by anonymous

Using a RUT955 in a car I would like to record the GNSS messages (every 5 seconds) during a 5 week road trip. I am afraid that the file becomes too large.

1) Is there a limit to the maximum file size of the recording (from filesystem perspective using a uSD card in extended mem mode before the card is actually full (64GB))

2) Would it be possible to change to a new file each day? How to set this using the WebUI / UCI?

3) Not tried this, but maybe a hack would be to do a daily reboot and add a user script that changes the gps.nmea_collecting.location?

  • uci set gps.nmea_collecting.location="Location-of-the-file-for-today"
  • uci commit
  • reload_config

4) Another solution I am working on is using a NMEA forwarding to a local port and catch the data using a python script (works) that then should send daily progress emails (todo ;-).

I just would like to have the build-in recording as a backup and for further analysis of difference between GPS/Galileo/etc.

1 Answer

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by anonymous


I assume you are concerned with the size of a single file with the filesystem? Given that you plan to create a new file every day, each file should not become excessively large. I would assume that the file would grow around ~500KB an hour.

I think that you are right about using UCI, and you can try using a script for this purpose. This would also allow you to name files by dates. For example:


# Get the current date

dates=$(date +'%Y%m%d')

# Set the new file location


# Update the gps.nmea_collecting.location

uci set gps.nmea_collecting.location="$loc"

uci commit

/etc/init.d/gpsd restart

Then, add this script to crontabs for daily execution:

  • crontab -e

0 0  * * * /etc/

You also have the option to install Python on your RUT device. So, for example, you can build a basic Python server and request NMEA from it when needed. Though, you will have to develop it yourself.

Kind Regards,


Best answer
by anonymous
Thanks for your quick reply. The crontab is a perfect solution!

Probably going to add the same script also to just after boot, to make sure that the filename/date is set correctly after a (re)boot.


Kind Regards,