Troubles decoding Kicksat transmissions

[S Charlesworth]

Greetings-

I'm part of a group planning to launch a high altitude balloon. We have a ca. 2013 KickSat sprite we were planning to send up as part of the payload. All's well with setting up and programming the Sprite itself, and we've verified it's chirping out transmissions, but we hit a bit of a wall at the gnuradio stage. To recap at first I was wary of trying to install the bits on my Mac laptop directly having read many sad stories of that experience, so I set up a Linux VM under VMWare, Ubuntu 'Bionic Beaver'. Unfortunately since that version isn't recognized via the script on the groundstation github repo we muddled through putting it on there, didn't have great experiences and eventually started getting warnings about the jack daemon. We were assisted in the effort by a real-life Linux admin who has done a lot with Gnuradio and SDR, in fact he built a pretty cool SIGINT tablet that was quite a hit at DEFCON so he knows his way around Gnuradio and Linux anyway. Anyhow where we ended up was he recommended going w/ the absolute latest version of Ubuntu and try again from the start whereas I am also weighing the option a) set up a VM (or laptop) w/ a version of Ubuntu that's at least recognized by the script or b) bite the bullet and see how I get on setting things up in MacOSX.

How that's going is yes I can install it just fine and it recognizes my RTL-SDR etc, but still some issues getting all the blocks I need. Oy. Anyhow we shall keep at it, any advice appreciated...

[S Charlesworth]

OK, a couple updates, we reverted to the last Ubuntu the install script recognizes (14.04), and after the install and clearing up some business of blacklisting some things so we could actually use the RTL-SDR, questions remain:

Not sure what I’m supposed to use for PRN0, PRN1. Project Persephone’s according to the spreadsheet are 22, 23, so I tried those.

I have multiple ‘SpriteDecoders’. One is: ./groundstation/gr-sprite/examples/SpriteReceiver2.grc

The other:

SpriteReceiver.grc - on the github is says ‘download from here: https://github.com/kicksat/groundstation/wiki/Installing-GNURadio-(Ubuntu)’

This one won’t run because no ‘window size’ is specified in the ‘Peak Decimator’ block. No idea what that needs to be. Looks like it’s ‘512’ on ‘SpriteReceiver2.grc’

The latest version of the github repo references ‘SpriteReceiver2’ but not ‘SpriteReceiver’ which appears to have gone missing, this is slightly confusing.

Long story short, I'm not having much luck w/ SpriteReceiver2.grc as I don't see anything really happening and I see it printing a series of zeroes. Perhaps I need a better antenna, I dunno.

[S Charlesworth]

Another update - I received a helpful email with some things to try re: setting up on MacOSX. So I will give that a try.

I have some lingering uncertainty on the PRN #s. Are those set in the hardware somehow or somewhere in the software (Energia config or such?) Just want to make sure I have all the proper info. Worst case, I just try a series of consecutive integers...

Many thanks and have a great Sunday,

Steve

[S Charlesworth]

Another update, compile failure:

clang: warning: -lboost_system-mt: 'linker' input unused [-Wunused-command-line-argument]

/Users/scharlesworth/spritestuff/kicksat-groundstation/gr-sprite/lib/correlator_cf_impl.cc:116:44: error: 

      implicit conversion from '_Complex double' to 'float' is not permitted in

      C++

        baseBand[k] = iBB[k]*cos(M_PI/2*k) + 1i*qBB[k]*sin(M_PI/2*k);

                    ~ ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

1 error generated.

make[2]: *** [lib/CMakeFiles/gnuradio-sprite.dir/correlator_cf_impl.cc.o] Error 1

make[1]: *** [lib/CMakeFiles/gnuradio-sprite.dir/all] Error 2

make: *** [all] Error 2

Went back to Linux, neither luck nor joy there either, although we did get a proper fully-functional gnuradio install that (tried) to run SpriteReceiver2.grc

I have handed things off to a less worn-down individual to examine further.

Have a good weekend,

Steve