[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Discuss-gnuradio] Doppler detection
From: |
jmfriedt |
Subject: |
Re: [Discuss-gnuradio] Doppler detection |
Date: |
Thu, 24 Aug 2017 07:25:41 +0200 |
I am also unable to understand what you aim (or problem) is but if it can be of
any use to you, a small movie of 24 hour of GRAVES radar recording is available
at
http://jmfriedt.free.fr/1707_graves_36h.ogg
Horizontal axis is Doppler shift in Hz (df=2*v/c*143.05 MHz, or a velocity of
750 km/h
for a 200 Hz Doppler shift, consistent will plane velocity): all the horizontal
lines are
nearby planes. I do not have the sensitivity for detecting satellites. If it
can be of any
help, since I struggled initially to figure out how to save spectra for
post-processing (as
opposed to the raw signals which would have taken too much disk space), my
gnuradio flowchart
is at http://jmfriedt.sequanux.org/170828_grc.png (the trick was to use to
stream to vector,
which I had not investigated prior to this project, and inform the filesink of
the vector
length at the output of the FFT).
JM
> Ok like the primary radar I have spent 7 years working on
>
> How do I pull out doppler shifted signal from a waterfall spectrum
>
> The doppler shift is slow though
>
> Not a chirp but a slow 5 minute chirp
>
> Andrew
>
>
>
> Sent from my iPhone
>
> > On 23 Aug 2017, at 8:05 pm, Marcus Müller <address@hidden> wrote:
> >
> > So, adapt the scale with which you look at things.
> >
> > I think your question could actually use a lot of "describe the problem
> > that you're actually having".
> >
> > The point is that you don't really seem to understand how you'd "pull the
> > doppler signals" out of a combination of signals. Now, we all love to help
> > each other, but with this, I'm really stuck with "I don't know what Andrew
> > needs help with". My gut feeling is that you haven't got a firm grip on
> > what Doppler estimation really is, or how you can do it:
> >> I guess this would require some sort of processing ?
> > GNU Radio can help you /implement/ that, but at least the basic principles
> > are universal. I'd have done very much the same as Chris: point you to
> > references, which will allow you to recognize the math behind Doppler
> > estimation from actual implementation.
> > Best regards,
> >
> > Marcus
> >> On 08/23/2017 07:42 AM, Andrew Rich wrote:
> >> Sorry you misunderstood my question
> >>
> >> I want the doppler shift of the satellites to be very distinct from the
> >> station with no doppler shift
> >>
> >> Much like doppler shift radar perhaps
> >>
> >> But the change in frequency can be minutes long for the satellite pass
> >>
> >> Andrew
> >>
> >>
> >>
> >>> On 23 Aug 2017, at 3:26 pm, Chris Kuethe <address@hidden> wrote:
> >>>
> >>> https://github.com/wnagele/gr-gpredict-doppler
> >>> https://github.com/daniestevez/doppler
> >>>
> >>> might be helpful or at least inspirational.
> >>>
> >>>> On Tue, Aug 22, 2017 at 9:58 PM, Andrew Rich <address@hidden> wrote:
> >>>> Sorry this is new to me
> >>>>
> >>>> I have just worked out I can see satellites in a waterfall display due
> >>>> to their doppler shift
> >>>>
> >>>> I think that lends itself to meteor shower
> >>>>
> >>>> Can gnu radio be used to assist pulling out the
> >>>> doppler signals from the non doppler ones ?
> >>>>
> >>>> I guess this would require some sort of processing ?
> >>>>
> >>>> Andrew
> >>>>
> >>>> Sent from my iPhone
> >>>>
> >>>> _______________________________________________
> >>>> Discuss-gnuradio mailing list
> >>>> address@hidden
> >>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
> >>>
> >>>
> >>>
> >>> --
> >>> GDB has a 'break' feature; why doesn't it have 'fix' too?
> >>
> >>
> >>
> >> _______________________________________________
> >> Discuss-gnuradio mailing list
> >> address@hidden
> >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
> >
--
JM Friedt, FEMTO-ST Time & Frequency/SENSeOR, 26 rue de l'Epitaphe, 25000
Besancon, France
- [Discuss-gnuradio] Doppler detection, Andrew Rich, 2017/08/23
- Re: [Discuss-gnuradio] Doppler detection, Chris Kuethe, 2017/08/23
- Re: [Discuss-gnuradio] Doppler detection, Andrew Rich, 2017/08/23
- Re: [Discuss-gnuradio] Doppler detection, Marcus Müller, 2017/08/23
- Re: [Discuss-gnuradio] Doppler detection, Chris Kuethe, 2017/08/23
- Re: [Discuss-gnuradio] Doppler detection, Andrew Rich, 2017/08/23
- Re: [Discuss-gnuradio] Doppler detection,
jmfriedt <=
- Re: [Discuss-gnuradio] Doppler detection, Andrew Rich, 2017/08/24
- Re: [Discuss-gnuradio] Doppler detection, Marcus Müller, 2017/08/24