Re: [Discuss-gnuradio] GNU radio

[Nick Foster]

Andrea, Andrew,

You're best off reading the source code: http://www.github.com/bistromath/gr-air-modes/

I also have a set of slides from the Gnuradio conference, but it doesn't go into detail into the decoder itself: http://www.nerdnetworks.org/~bistromath/adsb.pdf

PPM is pretty straightforward to decode. There's a preamble detector (air_modes_preamble.cc), which uses stream tags to mark possible valid Mode S packets, and a slicer (air_modes_slicer.cc) which gets bits out of it. That's all pushed through a message queue into the Python app, which does all the parsing,  position decoding, etc.

Feel free to contact me personally with ADS-B- or gr-air-modes-specific questions, that traffic probably doesn't belong on the list.

--n

On Wed, Sep 21, 2011 at 11:35 AM, Andrea Montefusco <address@hidden> wrote:

Nick,

could you give me a pointer to the schema of your decoder ?
It seems to me that was available somewhere but I didn't manage to retrieve it.
Thanks in advance

       *am*

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