Hi, I’m interested in decoding data.
I have read posts in here about decoding using sox and gr_satellites, which is about changing .ogg to .wav and decoding it using gr_satellites.
I also saw the artifacts(hdf5) has data from iq file.
Therefore, i guess there must be a way to get data from artifacts(hdf5) but i can’t not find a way or related software still.
How can i get the data from hdf5?
It is currently under development. I think @kerel had some tools ready to read these files. However these data will not be useful for decoding, as they are actually the type of artifacts that will replace the waterfall image in the future.
I see. Thanks for the replying!
The artifact files contain essentially the spectrogram data which is also shown in the waterfall PNG image, but no IQ data. Thus, they are not useful when trying to decode data.
regarding development:
Currently there are no active development efforts for SatNOGS artifacts.
After I checked some hdf5 files, there are 1,024 samples for frequency(x-axis). Is it the reason hdf5 files can not have data? I think the waterfall image in SatNOGS observation pages are from IQ data. Therefore, the image may have more samples for x-axis.
The current purpose of a SatNOGS artifacts is to provide a machine-readable spectrogram. Sample frequency and FFT size are motivated by upload and storage constraints.
For IQ data, there are much better established data formats (e.g. compress or raw samples + sigMF) and vastly different requirement on upload and storage. Let us know if you are interested in operating a SatNOGS station that uploads IQ data and you will find guidance here.
In IQ data from recordings of which satellite(s) are you interested specifically? Maybe you can find someone here willing to provide it using their station.
Thank you for the kind explanation!
I wasn’t curious about a particular satellite.
I was thinking about demodulation from artifacts(hdf5). If the mode is FSK, I thought it would be possible to decode it because I know the frequency at a certain point in time. If that’s possible, I thought I could generate a binary data from artifacts.
Thank you again!
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