This weekend, Mike DK3WN caught GOMX-3 downloading a good amount of data. See his post here. This data consists mainly of the satellite retransmitting a lot of beacons that were generated during the last 16 hours or so.
GomSpace has recently released a complete parser for GOMX-3 beacons of type 1 0 (these are the beacons that contain ADS-B data). I have already incorporated this code into my gr-ax100 fork.
The binary data in KISS format (almost 250KB) and the parsed beacon data received during this data download is in gist. Probably the most interesting thing is the ADS-B data. Below you can see all the aircraft on the map. Clicking on any of them will show the details for that aircraft.
Since the orbit of GOMX-3 has an inclination of 51.6º, the satellite doesn’t usually detect aircraft above 55ºN or below 55ºS. GomSpace has an image which shows lots of flights received with GOMX-3. There, the major air routes and hubs are apparent.
Hi Dani,
Thanks for the decoder upgrade, and the ADS-B to KML converter! Interesting that Mike was able to receive so many packets of data. So far, I have only seen such packets every 10 seconds.
We very much appreciate your showing us the way.
Best,
Bob
GomSpace is in Denmark, and Mike is close by. They only download stored data over their ground stations. They have several in Europe, but presumably none in the US, so you will only get real-time telemetry.
I forgot to say that to use the KML converter you need to add a header and footer to obtain a valid KML file. I have updated the README accordingly.
Please anybody can tell me which program/s to use to dedode
the Gomx-3 Bird?
Thanks
Enzo
https://github.com/daniestevez/gr-ax100
Thanks destevez,
at the link you gave me ise several files. Which one i need?
Thanks
Enzo
You need to download the whole git repository, compile and install. It’s a GNUradio out-of-tree module.
Daniel is there Any tutorial installation as i am not an Linux user but just a Windows one.
Any help quell be really appreciated.
Enzo
Hi Daniel, I am not a Linux and Gnu Radio user but with the help of some friends I am trying to install your gr-ax100. Created a virtual machine on win 7.1 using VMware 12,intalled Ubuntu 12.04 and Gnu Radio 3.7.4,installed KA9Q libfec,installed gr-synctags,try to install gr-ax100, cmake ok, make generated an error “/bloks/gnuradio/pack_k_bits.h”. Please advise, tnx.
With that information, I can’t say what is wrong, apart that it’s really strange that it gives an error there. Please email me the full compile log to try to see what the problem is.
In any case, pack_k_bits is not really necessary in the latest version of my gr-ax100 fork, so I might remove it if I see that it gives problems.
Unfortunately the Ubuntu/GnuRadio expert is flew away and will be back in four months. If he has free time he will try to fix it by remote using teamviewer, at present I haven’t the compile log. Thanks anyway, I will continue to watch the uge signal from GOMX-3 without decoding.
Hi Dan, I am still having problems trying to install your gr-ax100 program. Installed Ubuntu 16.04.1 LTS in dual boot with Windows 10,
Gnuradio, KA9Q libfec, gr-synctags, gr-csp-master, gr-kiss-master and gr-ax100, all with cmake-gui creating .deb packages.
When i go to run the gnuraadio with th comnand “gnradio-companion”, i get this error either in the program znd in the terminal window:
<<>>
Preferences file: /home/vincenzo/.gnuradio/grc.conf
Block paths:
/home/vincenzo/.grc_gnuradio
/usr/local/share/gnuradio/grc/blocks
/usr/share/gnuradio/grc/blocks
Loading: “/home/vincenzo/HAM/gr-ax100-master/examples/ax100_rx_fm_demod.grc”
>>> Error: Block key “ax100_adsb_kml” not found
>>> Error: Block key “ax100_beacon_parser” not found
>>> Error: Block key “ax100_gomx3_rs_decode” not found
>>> Error: Block key “csp_check_crc” not found
>>> Error: Block key “csp_print_header” not found
>>> Error: Block key “synctags_fixedlen_tagger” not found
>>> Done
Showing: “/home/vincenzo/HAM/gr-ax100-master/examples/ax100_rx_fm_demod.grc”
where am i still missing?
i’ve also sent you an email but did not get a reply yet.
thanks
Enzo -IK8OZV
Hello Daniel,
thank you for your ax100 GNURadio fork.
Testing ax100_rx_fm_demod.grc (GRC 3.7.9 on Ubuntu 16.04, Wav file source: gomx.wav) i get this error: AttributeError: ‘module’ object has no attribute ‘gomx3_rs_decode’ (please see log details below).
Same with GRC 3.7.10.
I wonder if I should downgrade GNU Radio version (maybe something changed recently in api) or just pay a little more attention in dependencies and complier stuff 😉
Any hint will be appreciated.
Cordially,
Gianfranco
Executing: /usr/bin/python -u /home/outis/GR_Modules/gr-ax100-master/examples/top_block.py
Using Volk machine: avx_64_mmx_orc
Traceback (most recent call last):
File “/home/outis/GR_Modules/gr-ax100-master/examples/top_block.py”, line 196, in
main()
File “/home/outis/GR_Modules/gr-ax100-master/examples/top_block.py”, line 184, in main
tb = top_block_cls()
File “/home/outis/GR_Modules/gr-ax100-master/examples/top_block.py”, line 132, in __init__
self.ax100_gomx3_rs_decode_0 = ax100.gomx3_rs_decode(True)
AttributeError: ‘module’ object has no attribute ‘gomx3_rs_decode’
Hi Gianfranco,
This looks like a swig problem. You can try just with python2.7 to debug.
$ python2.7
Python 2.7.10 (default, Nov 19 2015, 10:01:32)
[GCC 4.8.5] on linux2
Type “help”, “copyright”, “credits” or “license” for more information.
>>> import ax100
>>> ax100.gomx3_rs_decode
If you can’t get ax100.gomx3_rs_decode in python, then there is some problem with installation. Sometimes, running “ldconfig” helps. Other times, it is some weird problem with swig that I’ve been unable to trace.
Hi Daniel,
thank you for your help!
I’m afraid it is an installation problem. Let’s hope it isn’t a swig weird behaviour.
gomx3_rs_decode is missing from python modules, but not from GRC modules list.
I’ll let you know if I find a solution.
Regards
Gianfranco
Help on package ax100:
NAME
ax100
FILE
/usr/local/lib/python2.7/dist-packages/ax100/__init__.py
DESCRIPTION
This is the GNU Radio AX100 module. Place your Python package
description here (python/__init__.py).
PACKAGE CONTENTS
adsb_kml
beacon_parser
gomx3_beacon
(END)
>>> ax100.beacon_parser
>>> ax100.gomx3_rs_decode
Traceback (most recent call last):
File “”, line 1, in
AttributeError: ‘module’ object has no attribute ‘gomx3_rs_decode’
No *decode* module in /usr/local/lib/python2.7/dist-packages/ax100/ directory either
Hello Daniel,
compiled everything from source (i.e. whole GNURadio project) and AttributeError is gone 🙂
Previous installation was on top of the Ubuntu official GNURadio package (apt-get install gnuradio).
Now I’m able to play the example flow ax100_rx_fm_demod.grc with your sample wav input file.
Enabling QT_GUI_Time_Sink block I can see the Amplitude graphic chart.
Problem is that is the only output I can get.
If I select “verbose=yes” in GOMX-3_RS_Decode, I get a sequence of “RS decode failed”.
I slightly modified gomx3_rs_decode_impl.cc in order to have a more detailed output, and i can see that the value of “data” is always constant, while data[0] moves in the range 0-255
E.g. “RS decode failed. data=2046796496 data[0]=117”
The value of “data” is constant in each play, but is different among different play times.
Apparently the values of data[0] seem to repeat in the same order in each play (last line is always data[0]=117, etc.).
I wonder where is the rub now – is the wav file somehow incomplete or there is still some installation/configuration issue?
Thank you
Regards
Gianfranco
My fault. I’ve checked everything again and it turns out that the sample .wav file that was linked in the README was from GOMX-1, not from GOMX-3.
I’ve updated the README to correct this. The correct sample file is gomx3.wav.
Also, make sure that the “multiply const” block in ax100_rx_fm_demod is -15 (this has to be adjusted depending on the polarity and volume of the demodulated FM audio).
With these changes, you should get some decodes.
Yes, thank you so much!
Still lots of “RS decode failed.”, but also decoded data (please see below).
If you say that it’s ok I’m more confident with my installation.
Since dependencies are a critical issue, may I ask you which path did you follow to build your modules?
I mean Ubuntu over Fedora or CentOS, Github or gnuradio package installation…
Thank you again for your prompt answer.
regards,
Gianfranco
Beacon type 1 0:
EPS:
Timestamp: 2016-05-08 10:01:40
Boost converter voltage: 11.615V, 11.628V, 7.709V
Battery voltage: 15.191V
Out current: 52mA, 68mA, 0mA, 68mA, 78mA, 8mA, 144mA
In current: 144mA, 412mA, 205mA
Sun current: 483mA
System current: 142mA
Temperature: -5ºC, -3ºC, -6ºC, -7ºC, -7ºC, -7ºC
Battery mode: 3
COM:
Timestamp: 2016-05-08 10:01:40
Board temperature: -6.0ºC
PA temperature: -5.3ºC
Last RSSI: -95dB
Last rferr: -739
Background RSSI: -112dB
OBC:
Timestamp: 2016-05-08 10:01:40
GSSb1 current: 0mA
GSSb2 current: 4mA
Flash current: 0mA
Temperature A: -7.2ºC
Temperature B: -7.1ºC
ADCS:
Timestamp: 2016-05-08 10:01:40
GSSb1 current: 6mA
GSSb2 current: 5mA
Flash current: 1mA
PWM current: 3mA
GPS current: 13mA
WDE current: 179mA
Temperature A: -7.7ºC
Temperature B: -7.4ºC
ADSB:
Timestamp: 2016-05-08 10:01:40
5V board current: 0mA
3.3V board current: 22mA
3.3V SD current: 0mA
1.2V current: 7mA
2.5V current: 0mA
3.3V FPGA current: 0mA
3.3V ADC current: 4mA
Last airplane:
ICAO 24 bit address: 0x0
Latitude: 0.0
Longitude: 0.0
Altitude: 0ft
Time: 1970-01-01 00:00:00
The RS decode failures are normal. If you set a high threshold in the Correlate Access Code block (6, for instance), it will trigger even on random noise. The RS decoder will then be unable to decode this “false packet” and catch the error. If you set a low threshold (1 or 2), it will be much harder to trigger on random noise, so almost everything that goes to the RS decoder will be a real packet. On the other hand, you’ll lose the chance to decode packets with several bit errors in the preamble.
Crystal clear.
Thank you for your kind support and kudos for the great job done!