Adding a new data decoder

2022-08-15T17:59:34Z

Arneir77: update link to satblog

== Introduction ==
This is one of the last steps on your way to add support for a satellite in SatNOGS and visualize it in the SatNOGS [[Dashboard]]. For the previous steps have a look at [[Satellite Mission Guide]] and [[Satellite operator manual]] (those two pages will probably be merged in the future).

==How to create the parser for a new satellite downlink==

For satellite downlinks where SatNOGS provides demodulated data, but no decoder exists yet.

#Find and read documentation of the satellite downlink.
#Extract raw frames either from satnogs-network or satnogs-db.
#*from network: Open good observations whith demodulated data,
#*:then open the observation via the API,
#*:copy the link to the payloads and download them (e.g. via wget)
#*from db: Export frames of your satellite (how?), then convert them from hex to raw
#Write the Kaitai Struct (.ksy-file)
#*Open the [https://ide.kaitai.io/ Kaitai WebIDE]
#*Create a new .ksy-format file (press the empty sheet button in the lower left)
#*Upload the previously fetched raw frames as example data (press the cloud button in the lower left, select all files with raw frames)
#*Write the kaitai struct following the guide [https://community.libre.space/t/starting-with-satnogs-decoders/3145 "Starting with satnogs-decoders"] (TODO: Move this guide into this wiki) Use existing parsers from the [https://gitlab.com/librespacefoundation/satnogs/satnogs-decoders satnogs-decoders] repository for reference.
#*The "doc:" section which defines all fields in front of the satnogs decoder kaitai structs can be ignored for now. They are ignored by kaitai, satnogs-specific and will be auto-generated in a later step.
#*Add a link to all the documentation of the satellite downlink which was used to write the kaitai struct (this can be done with a doc key)
#Check the results of your parser
#*If another parser exists, cross-check your results with the output it provides.
#*Sometimes there are examples frames or examples recordings provided. Use them for verification (if the data is well-known.)
#Generate the fields definition using the [https://gitlab.com/librespacefoundation/satnogs/satnogs-decoders/blob/master/contrib/generate_field_docstring.py generate-field-docstring.py script] (TODO: Add detailed documentation here and in the README)
#Fork the [https://gitlab.com/librespacefoundation/satnogs/satnogs-decoders satnogs-decoders] repository and add your decoder as described in the [https://gitlab.com/librespacefoundation/satnogs/satnogs-decoders/tree/master#adding-a-new-decoder README]
#Create a commit with your new kaitai struct, push it to your fork and submit a Merge Request to satnogs-decoders
#Done.

Next step: [https://wiki.satnogs.org/Telemetry_Dashboards Add a dashboard to visualize the new data]

==See also==

*[http://doc.kaitai.io/user_guide.html Kaitai Struct User Guide]
*[https://ide.kaitai.io/ Kaitai WebIDE]
*[https://gitlab.com/librespacefoundation/satnogs/satnogs-decoders satnogs-decoders] repository
*[[Decode Telemetry and Packets]]
*[https://www.satblog.info/ Satellite specific telemetry decoders] (German)

[[Category:Develop]]
[[Category:Software]]
[[Category:RF Modes]]

SatNOGS Wiki - User contributions [en]

Adding a new data decoder