Observation 3442532: NORBI (46494) - SatNOGS DB entry incorrect?

Regarding Observation 3442532

I’ve been receiving Norbi (Norby) LoRa telemetry via a separate system ( https://t.me/s/FOSSASAT_DATA?q=kk6now ) but I never thought of looking at its GFSK datastream. In this observation, it appears to have been decoded.

My question is: Why does the SatNOGS DB show “No Decoders Found” and no “Data Frames Decoded - 30 Days” ? https://db.satnogs.org/satellite/46494#data


“Demodulated” you mean :slight_smile:

Because no one has supplied any decoders for NORBI

No decoder = no decoded packets :slight_smile:

As @pierros said, for decoding frames from NORBI we will need a decoder. If you are interested, it seems that pdf in this post Soyuz 2-1b Fregat-M 2020-09-28 describes the encoding, so it should be possible to create a kaitai struct that will generate NORBI decoder and allow frames to be decoded and maybe feed a dashboard in dashboard.satnogs.org.

PS I’ve added the LoRa transmitter in DB as we didn’t have it.

@pierros, you are correct. I misinterpreted decoded as meaning demodulated.

@fredy, thanks for pointing out that thread. I’ll investigate creating a decoder.

If helpful, anyone is certainly welcome to the Norbi KSY file at https://www.qsl.net/k/k4kdr//downloads/norbi/norbi.ksy

One use of that is with the Kaitai online IDE at https://ide.kaitai.io/# as shown in this tweet from Oct-2020: https://twitter.com/scott23192/status/1320263466649870337

-Scott, K4KDR

Thanks Scott @K4KDR for all your efforts on Norbi. I’ve imported your KSY file into the IDE.

Any suggestions on how to get data out of SatNOGS into the Kaitai online IDE? It appears the IDE only imports raw files and not an ASCII text representation.

Fredric KK6NOW

@K4KDR, Sorry for the newbie question. Just realized clicking on the observation URL in the data tab will download the binary file.

@fredy Why not have a data button in the UI Downloads section of the UI?

Now on to accommodating the Ax.25 header…

To view “real” data based on the definitions in the KSY file, I have always grabbed the proper portion of the decode (starting with ‘8EFFFFFFFF’ shown below from a CSV export from SatNogs DB) and piped it thru ‘xxd -r -p’ to create the type of hex file that the Kaitai online IDE requires:


… no doubt there are less mechanical / hands-on ways to do it, but this has served me well when I want a convenient way to view meaningful values from the raw data.

Not sure I understand what you mean. Do you mean a way to export frames?

Sorry for the confusion. I was struggling to find a way to download (export) the frame as a binary file from the data tab. I accidentally discovered one can do so by clicking on the url of the file.

My suggestion was to add a “data” button in addition to the “audio” and “waterfall” buttons in the Downloads section (on the left side of the screen.)

Upon reflection, this presents a problem when there are multiple frames present in an observation. Do you create a zip file containing all frames, each in a separate file?

The current method works fine, but I believe it’s undocumented.

Oh! I thought you were talking about the “Data” tab in the DB entry of the satellite but you were talking about the “Data” tab in Network observations. Unfortunately in Network there isn’t such a functionality, please open an issue in https://gitlab.com/librespacefoundation/satnogs/satnogs-network/-/issues for adding this feature.

PS Until this is implemented you can use the observations API endpoint and get the links to the files, for example: https://network.satnogs.org/api/observations/3466776/