RTKCONV does not time corr .ubx file if Time Start - Time End options are selected

[John-2222]

RTKCONV does not time corr .ubx file if Time Start - Time End options are selected

[rtklibexplorer]

Fixed with commit on 12/8/23

[bpguillem]

I can confirm there is an issue with convbin when using with -ts -te.

For example, the .nav ouput file only gets data from 3-4 satellites when I convert a specific 15-min interval from the .ubx. Debug trace shows messages such as "3 ubx rxmsfrbx nav unsupported sat=3 len=56". For the same time interval, when converting the entire .ubx, the .nav file gets data from 10-12 sats.

Note that the ubx file I used is OK. I parsed it using pyubx2.ubxreader, cropped the 15-min interval of interest and saved to an ubx file. Then I used convbin on the entire cropped file without -ts -te and the output was OK.

I do not know the underlying processing steps, hope this information helps.

[rtklibexplorer]

These sound like two different issues. If you send me an email at [email protected] with the file in question and the exact command lines used I will take a look.

[rtklibexplorer]

Thank you for sending the file. I was able to duplicate the issue you are seeing. Typically, there are many, many duplicate nav messages in the raw receiver data since the receiver message update rate is much more frequent than the rate that the actual ephemeris is being updated in the messages. RTKLIB defaults to filtering out all of the duplicates and only logging the initial occurrence of each message. Unfortunately, it is not considering the time window defined by "ts" and "te" when doing this, so it is only logging the messages that changed during this window. It would be more useful if it logged the initial messages for each satellite during this window as well as the ones that changed.

I will look into updating the code to do this, hopefully in the relatively near future. In the meantime, there are at least a couple of workarounds that you could use. If you add "-ro -EPHALL" to the CONVBIN command line, CONVIBIN will log all navigation messages, not just the unique ones. This will fix the problem, but will add many duplicate messages to the nav file. These will be filtered out in the post-processing run so will change the post-processing execution time only very slightly, but the nav files will be somewhat larger.

The other option would be to create only the observation files for each time window, and then create one navigation file for the whole dataset. If you specify the name of the output files with the "-n" and "-o" options in the command line, then CONVBIN will only create the files you specify. This will allow you to choose output of just the observation file or just the navigation file.

For more details on the CONVBIN command line options, see the user manual at https://rtkexplorer.com/pdfs/manual_demo5.pdf.