Hello, I have some needs and I’d like to know if GnuRadio can help me
with it. I have already read some material at GR website and I didn’t
get the answer.I need to receive and send packets with a specific
protocol called MAVLink, used in mini UAVs. More specifically I am
thinking about developing a sniffer.I don’t have sdr hardware for now,
then for starting I am thinking on simulation. My doubts are as follows:
- Is it possible to implement a new protocol for sending and receive
packets? (MAVLink protocol)
- My idea is to simulate the exchange between a UAV and a control ground
station. Would it possible to do it?
Thanks in advance.
Hi Paulo,
GNU Radio gives you but the framework to write and connect signal
processing blocks, as well as a nice set of “standard” blocks.
Among the functionalities available there are means to generate packets
and process the same.
If you know that if you can capture the signal, you could
mathematically/algorithmically analyze it, it’s basically possible to
implement this in GNU Radio.
That being said, it’s not really easy to implement a complete packeted
standard in GNU Radio since that might be a “logically” complex task,
involving different modulations, synchronization, collision detection,
arbitration, resend requests and much more. However, there are several
examples of people being able to decode received signals. I like to
point gr-ieee802-11 (WLAN packets transceiver), and for a “simpler”
system gr-air-modes (air traffic control message decoding).
Greetings,
Marcus
Hi!
Of course it would be helpful if you had a capture device if your
motivation was to capture signals of a system. Also, it will give you
something to test your reception algorithms on.
Greetings,
Marcus
Hey,
I have the feeling that there maybe a misunderstanding about what
MAVlink really is. The MAVlink protocol as such is serialization library
that is used to transfer information, i.e. serialized data structures,
between mobile and stationary devices rather than a whole “communication
system”. You can transfer MAVlink messages over any kind of transport
system such as Wifi, bluetooth, Zigbee or any proprietary system.
So what you probably want is to receive and decode the communication of
that transfer system, maybe using GR, and then decode the actual payload
with the MAVlink library.
Cheers
Andre
Right, I’ve played with MAVlink before and as said it is not a wireless
standard, you can send it over hard link serial if you want. I’m
assuming
your are sending the MAVlink over a pair of serial-RF adapters as is
usual.
http://copter.ardupilot.com/wiki/common-using-the-3dr-radio-for-telemetry-with-apm-and-px4/
Seems to be what most use ( I have a pair of these as well ). If you
look
at the technical section your can see they list FHSS GFSK as the
modulation. I would look into the datasheet for the chip for more
details.
I would recommend just doing the RF demodulation in GNUradio and then
send
the packets to an external program for further processing.
~Andrew
On Sat, Jun 28, 2014 at 8:06 AM, Andre P. <