Re: [Discuss-gnuradio] Doppler detection

[Andrew Rich]

Sent from my iPhone

> On 24 Aug 2017, at 3:25 pm, jmfriedt <address@hidden> wrote:
> 
> 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
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>>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio  
>>> 
> 
> 
> -- 
> JM Friedt, FEMTO-ST Time & Frequency/SENSeOR, 26 rue de l'Epitaphe, 25000 
> Besancon, France