SatNOGS Wiki - User contributions [en]

Decode Telemetry and Packets

2019-11-12T11:03:22Z

N5fxh: Add reference about SatNOGS processing in the section

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==
[[File: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:

*[[SoX_CW|CW]] (Continuous Wave, Morse Code)

===References===

*Chris Bagwell SoX − Sound eXchange http://sox.sourceforge.net/sox.html

==Fldigi in audio playback mode==
Fldigi can be used to decode a variety of data modes.

*[[Fldigi_CW|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===

*AC2CZ FoxTelem - AMSAT Ground Station Software http://www.g0kla.com/foxtelem/

==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===

First convert to raw sound file (sampling frequency 22050Hz) using sox 
sox -t ogg $file -r 22050 -t raw file.raw $soxopts 

Then use multimon-ng with AFSK1200 decoder 
multimon-ng -t raw -a AFSK1200 $file.raw

You can add more decoders if needed with additionnal "-a" options

===References===

*Elia Oenal Multimon-ng https://github.com/EliasOenal/multimon-ng

==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

Both commands can be combined with a pipe: 
<nowiki>sox -t ogg satnogs_386252_2018-12-29T02-54-45.ogg -esigned-integer -b 16 -r 48000 -t raw - | direwolf -B 1200 -b 16 -n 1 -r 48000 -q hd -t 0 -q h -q d -d p -d t -a 0 -</nowiki> 
([https://community.libre.space/t/observation-386252-x-cubesat-42707/3093/2 source])

==QSSTV==
[http://users.telenet.be/on4qz/qsstv/index.html QSSTV] is a modem software to send and receive SSTV
([https://en.wikipedia.org/wiki/Slow-scan_television Slow Scan Television]).

===Usage===

*Download the ogg file and convert it to wav with: <nowiki>sox satnogs_154162_2018-06-06T12-46-40.ogg output154162.wav rate 48000</nowiki>

*Open QSSTV and specify "Sound>Sound Input: from file"
*Press the play button and you will be asked to select the previously generated wav file. The decoding should start now.

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

 

==WXtoImg==

WXtoImg is a program used to produce neat weather pictures from APT format receptions of NOAA satellites.

SatNOGS client produces automatically such weather map. However, if you want to add overlays or test some part of the processing, you can do it manually.

It uses a .wav file and produces weather picture with possible nice overlays (frontiers, colors...).

===Usage===

*Download for example the ogg file from observation #1193773 and convert it to wav with:

sox satnogs/satnogs_1193773_2019-11-12T07-13-50.ogg -r 11025 satnogs/satnogs_1193773_2019-11-12T07-13-50.wav

*Then invoke command line interface of WXtoIMG with:

wxtoimg -t n -e HVC -N satnogs/satnogs_1193773_2019-11-12T07-13-50.wav > satnogs/satnogs_1193773_2019-11-12T07-13-50.png
 

===References===
WXtoImg restored: https://wxtoimgrestored.xyz/
 
==Scholarly Articles==
[[Category:Telemetry]]
__NOEDITSECTION__

Decode Telemetry and Packets

2019-11-12T10:59:25Z

N5fxh: add WXtoImg processing example

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==
[[File: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:

*[[SoX_CW|CW]] (Continuous Wave, Morse Code)

===References===

*Chris Bagwell SoX − Sound eXchange http://sox.sourceforge.net/sox.html

==Fldigi in audio playback mode==
Fldigi can be used to decode a variety of data modes.

*[[Fldigi_CW|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===

*AC2CZ FoxTelem - AMSAT Ground Station Software http://www.g0kla.com/foxtelem/

==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===

First convert to raw sound file (sampling frequency 22050Hz) using sox 
sox -t ogg $file -r 22050 -t raw file.raw $soxopts 

Then use multimon-ng with AFSK1200 decoder 
multimon-ng -t raw -a AFSK1200 $file.raw

You can add more decoders if needed with additionnal "-a" options

===References===

*Elia Oenal Multimon-ng https://github.com/EliasOenal/multimon-ng

==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

Both commands can be combined with a pipe: 
<nowiki>sox -t ogg satnogs_386252_2018-12-29T02-54-45.ogg -esigned-integer -b 16 -r 48000 -t raw - | direwolf -B 1200 -b 16 -n 1 -r 48000 -q hd -t 0 -q h -q d -d p -d t -a 0 -</nowiki> 
([https://community.libre.space/t/observation-386252-x-cubesat-42707/3093/2 source])

==QSSTV==
[http://users.telenet.be/on4qz/qsstv/index.html QSSTV] is a modem software to send and receive SSTV
([https://en.wikipedia.org/wiki/Slow-scan_television Slow Scan Television]).

===Usage===

*Download the ogg file and convert it to wav with: <nowiki>sox satnogs_154162_2018-06-06T12-46-40.ogg output154162.wav rate 48000</nowiki>

*Open QSSTV and specify "Sound>Sound Input: from file"
*Press the play button and you will be asked to select the previously generated wav file. The decoding should start now.

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

 

== WXtoImg ==

WXtoImg is a program used to produce neat weather pictures from APT format receptions of NOAA satellites.

It uses a wav file and produces weather picture with possible nice overlays (frontiers, colors...).

=== Usage ===

* Download for example the ogg file from observation #1193773 and convert it to wav with:

sox satnogs/satnogs_1193773_2019-11-12T07-13-50.ogg -r 11025 satnogs/satnogs_1193773_2019-11-12T07-13-50.wav

* Then invoke command line interface of WXtoIMG with:

wxtoimg -t n -e HVC -N satnogs/satnogs_1193773_2019-11-12T07-13-50.wav > satnogs/satnogs_1193773_2019-11-12T07-13-50.png
 

=== References ===
WXtoImg restored: https://wxtoimgrestored.xyz/
 
==Scholarly Articles==
[[Category:Telemetry]]
__NOEDITSECTION__

Satellite Operator Guide

2019-06-05T19:53:42Z

N5fxh: /* Integration in the Satnogs network */

===Early stage of the project===
It's strongly advised to get in touch with the AMSAT of you country at the beginning of your project. It enables that the radio amateur requirements are taken in account at the early stage on your project. It avoids false expectations.
===Frequency===
First you need to know if you want to use a radio amateur frequency. This kind of frequency obey to special rules : no commercial use, and the satellite must be used by the radio amateur community more than 20% of it time. The service from the satellite can be a repeater, or any other experiment.

You need to ask the AMSAT of your country to help you to get a radio amateur frequency coordination from IARU your allocation.
It will take time : usually between one year and six months.

If you don't ask for an IARU coordination, the launcher of your satellite will not allow you to launch the satellite. In the past this was allowed, but today it's no more possible.

===Open your transmissions===
To comply with regulations, you will need to make publicly available all the TM packet format, we advise you to use a Kaitai Struct for it.
You also need to give any gnuradio flow chart that are useful to receive your data, and any picture decoder software if available. The preferred programming language for them is python. It's also a good practice to give raw recording of transmission to be able to test all the software chain.

===Integration in the SatNOGS network===
You need to create a post on the community forum with all this details :
- satellite name
- frequencies
- modulations
- link to TM format
- link to picture decoder

You are welcome to discuss with us on IRC (#satnogs on freenode)

Satellite Operator Guide