Re: [Discuss-gnuradio] Doppler detection

[jmfriedt]

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