gr-radar is probably still a great starting point. I was playing around
with it just recently, and will be contributing some fixes to gr-radar
in the next few week.
B210 support, I think, is not natively available. I was going to
characterize the TX/TX leakage, I'm not entirely sure how well it'll
fare for radar applications. In you case, leakage could be drown out
your measurements, but maybe it won't.
On 02/09/2018 12:48 PM, Tilen Matkovič wrote:
> thanks for quick reply!
> I was aware of range resolution equation, apparently I didn't specify
> project enough and wasn't really paying attention while reading some
> articles :/.
> Goal of my project would be to measure breathing/heartbeat rate of a
> human using FMCW radar in GNU radio. I just realized that I do not need
> to measure the distance of some object (human chest in my case), but
> only the phase variation, which would be much more precise for breathing
> monitoring than technique used in gr-radar, with some other limitations.
> I believe that beam antennas would help me, so I will try to use them
> also, once I understand theory and get it working in implementation.
> Article and webpage that helped me to understand such monitoring:
> Smart Homes that Monitor Breathing and Heart Rate
> - http://witrack.csail.mit.edu/vitalradio/content/vitalradio-paper.pdf
> If such implementation for monitoring phase variation already exists in
> GNU radio, please point me in right direction :)
> 2018-02-08 19:02 GMT+01:00 Sebastian Müller <gse...@gmail.com
> Hi Tilen,
> Am 8. Februar 2018 um 16:31:37, Tilen Matkovič
> (matkovic.ti...@gmail.com <mailto:matkovic.ti...@gmail.com>) schrieb:
>> Hello everyone,
>> I am working on a project where I am using radars to measure
>> distance/range from one point to another (with relatively high
>> range resolution - range of centimeters or even millimeters).
> Generally I’m not sure if you will achieve this with the B210
> hardware you mention later. Keep in mind the range resolution
> equation for radar:
> dr >= c/(2*B)
> For a range resolution of 1 cm you’ll need a signal bandwidth of 15
> GHz , while the URSP has a maximum frequency coverage of up to 6
> GHz, which means your center frequency plus half the bandwidth must
> be less equal 6 GHz. Common radars, for instance in automotive
> applications, work on a center frequency near 100 GHz, allowing much
> higher bandwidths!
>> I found the gr-radar (https://github.com/kit-cel/gr-radar/
>> <https://github.com/kit-cel/gr-radar/>) module for GNU radio,
>> which already has some implemented radar techniques, the most
>> promising for me would be the FMCW radar. But the github
>> repository was not updated in years, so I am asking you guys if
>> some of you may know some alternatives for GNU radio (googling
>> radar gnuradio was not so successful) or maybe anyone has already
>> worked with gr-radar.
> I’m not aware of any other projects, but I’ve used gr-radar myself.
> It definitely works in the real world, which you can see on Stefan’s
> Youtube channel .
>> Now what exactly is my problem - I managed to get the gr-radar -
>> FMCW working on one USRP B210 (with TX/RX and RX2 using
>> omnidirectional antennas). I was playing around with modifying
>> some of the variables but I am still not getting useful range data
>> (mostly it is constant, even if moving both of the antennas for a
>> few meters or putting some obstacles in between). Modifying the
>> samp_rate or sweep_freq, and others (samp_cw, samp_up, samp_down)
>> has also not given me useful results.
> The original setup for gr-radar consisted of two USRP N210,
> connected with a MIMO cable. It never ran on a B10, though there
> were some attempts, that seem to never have been further pursued .
> Also, since you’re using omnidirectional antennas with FMCW, you’ll
> detect a lot of static objects in *all* azimuth angles, while
> gr-radar was designed for one target only IIRC. So assuming it
> theoretically could work on a B210 (please let us know!!), I would
> propose to use beam antennas and try to use the dual CW waveform,
> which only detects moving objects.
> Let us know about any progress :)
>> Perhaps I am doing something wrong and not understanding the
>> theoretical principles about radars/signal processing or maybe the
>> FMCW flowgraph is not implemented correctly? I also have to
>> mention here that author (on github) only tested the FMCW
>> flowgraph in the simulation (which works ok), but not on the hardware.
>> Thanks for your help.
>> Discuss-gnuradio mailing list
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>  http://www.radartutorial.eu/01.basics/Range%20Resolution.en.html
>  https://www.youtube.com/channel/UCv7cqqFkkiRFJIGkNEyMu3g
>  https://github.com/kit-cel/gr-radar/issues/19
> Sebastian Müller
> gse...@gmail.com <mailto:gse...@gmail.com>
> PGP ID DC2AA3EE
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