RTKLIB: Missing data samples

I have deleted this post because I really did not have a good understanding of the issue of missing measurements in the base station data when I originally wrote this.  The problem and solution are better explained in this post on moving-base solutions where the issue is more relevant.

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4 thoughts on “RTKLIB: Missing data samples”

  1. Ah yes you are completely right: the base station receiver experiences a power cycle!
    The clock bias changes, changing all the code phases but this does not matter as RTKLIB handles well clock jumps. However, when the base restarts the carrier phase measurements are arbitrarily reset so the number of cycles is totally uncorrelated with the last good epoch. That explains it, thank you so much!
    I also had the feeling that resetting the phase bias states might not have been enough: I will take a look to which other states I should be resetting. Thank you very much again for your insight! Michele

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  2. Hello, thanks again for the great work.
    I think the problem I experienced could also be correlated with the above, see my post on FOSS-GPS:
    http://lists.osgeo.org/pipermail/foss-gps/2016-June/001638.html

    I am suspecting also your development branch would not recover cleanly, but would you please be so kind to take a look at it?
    I feel that the same problem would come back in many real-life scenarios and so it would be worth fixing in a clean way.

    For your reference, the dataset is here
    https://www.dropbox.com/s/igwt9jsh8pco1bs/160531n-aann.zip?dl=0

    All the very best,
    Michele

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    1. Hi Michele. I think you are probably right that these two issues are related. I downloaded your data and confirmed my change not only does not fix your problem but actually makes things even worse. I’ve removed the change from my code until I understand better what is going on. I agree it would be nice to have a clean fix for this and will see if I can add anything to what you have already done.

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      1. Hi Michele. It looks like there may be more going on in your base station data than just some missing samples. Possibly some sort of end of month clock reset? There are large jumps in all of the raw pseudorange and carrier phase measurements after the gap which look like they were caused by a large jump in the receiver clock. This causes jumps in all of the phase-biases. Your fix to reset all the states looks like a reasonable way to handle this. The only thing I can suggest is that you are resetting all the states, not just the phase-bias states. Most of the time this probably doesn’t make any difference, but if you had some of the other states enabled for atmospheric correction or IC biases, you might not want to reset those.

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