Difference between revisions of "Decode Telemetry and Packets"

From SatNOGS Wiki
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a variety of modes among which: CW, AFSK, FSK...
 
a variety of modes among which: CW, AFSK, FSK...
  
=== How to ===
+
=== How to CW ===
 
First you have to use sox to convert ogg files from SatNOGS download to 22050Hz raw file: <br>
 
First you have to use sox to convert ogg files from SatNOGS download to 22050Hz raw file: <br>
 
sox file.ogg -r 22050 file.raw gain 6 <br>
 
sox file.ogg -r 22050 file.raw gain 6 <br>
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Then you must apply on the raw file the proper decoder: <br>
 
Then you must apply on the raw file the proper decoder: <br>
 
multimon-ng -a MORSE_CW -t raw file.raw
 
multimon-ng -a MORSE_CW -t raw file.raw
 +
 +
=== How to AFSK ===
 +
 +
sox -t ogg $file -r 22050 -t raw ${file%.ogg}.raw $soxopts
 +
multimon-ng -t raw -a AFSK1200 ${file%.ogg}.raw
  
 
=== References ===
 
=== References ===

Revision as of 16:59, 14 June 2018

There are several tools available to decode telemetry and packets. SatNOGS provides some built-in demodulators for various data formats. There are also additional tools that allow you the decoding of telemetry.

Built-in demodulators

SatNOGS-Observation-Data.png

Although the SatNOGS servers support many satellites with many modes, only the following modes are supported with built-in demodulators:

  • APT (Automatic Picture Transmission)
  • AFSK 1k2 (Audio Frequency Shift Keying)
  • AX.25 (Amateur Radio adaptation of X.25 packet protocol)
  • CW (Continuous Wave, Morse Code)
  • DUV (Data Under Voice)
  • GFSK 9k6 (Gaussian Frequency Shift Keying)
  • FSK 9k6 (Frequency Shift Keying)
  • LRPT (Low Resolution Picture Transmission)

External demodulator/decoders

If for some reason, the above built-in decoders are not doing enough, there are many Satellite specific telemetry decoders. Also, there are more generic decoders listed below.

SoX - Sound eXchange

SoX is the Swiss Army knife of sound processing programs. SoX is cross-platform and is available for many operating systems (Windows, Linux, MacOS X, etc.).

SoX supports demodulating the following modes:

  • CW (Continuous Wave, Morse Code)

References

Fldigi in audio playback mode

Fldigi can be used to decode a variety of data modes.

  • CW (Continuous Wave, Morse Code)

FoxTelem for FOX1 series satellites

FoxTelem currently supports decoding DUV telemetry the following satellites:

  • AO-85 (Fox-1A)
  • AO-91 (Radfxsat / Fox1-B)
  • AO-92 (Fox1-D)
  • Fox-1Cliff, and
  • Fox-1E.

References

multimon-ng

Multimon-ng is a general purpose decoder. It can take wav or raw files and decode a variety of modes among which: CW, AFSK, FSK...

How to CW

First you have to use sox to convert ogg files from SatNOGS download to 22050Hz raw file:
sox file.ogg -r 22050 file.raw gain 6
The gain is in dB and has a considerable impact on the decoding in the special case of CW. You have to adjust gain to get proper decoding.

Then you must apply on the raw file the proper decoder:
multimon-ng -a MORSE_CW -t raw file.raw

How to AFSK

sox -t ogg $file -r 22050 -t raw ${file%.ogg}.raw $soxopts multimon-ng -t raw -a AFSK1200 ${file%.ogg}.raw

References


Direwolf

Direwolf is a software encoder/decoder for APRS (AX.25). It can take raw files and decode APRS.

How to

First you have to use sox to convert ogg files from SatNOGS download to 22050Hz raw file:
sox file.ogg -esigned-integer -b 16 -r 48000 file.raw

then launch direwolf direwolf -B 1200 -b 16 -n 1 -r 48000 -q hd -t 0 -q h -q d -d p -d t -a 0 - < file.raw


References

Direwolf WB2OSZ https://github.com/wb2osz/direwolf

Scholarly Articles