Re: [Discuss-gnuradio] Getting signal from a LEO Satellite? ( Doppler shift handling)

If you have a tracking dish, you might want to look at the FLL (freq lock loop) band edge block.  There was a talk on it during GRCON17 https://drive.google.com/file/d/0B-CV_07uSBIuQUVlNDFUX1BqZk0/view

If you have a symmetric signal spectrum w/ a generally flat channel (which tends to be satcom signals) then this might work as well.

Jared.

On Thu, Oct 26, 2017 at 5:02 AM, mehtap özkan <kurtulmehtap@gmail.com> wrote:

Thank you.

Should we adjust the Loop Bandwidth to track the signal correctly? 

2017-10-26 14:20 GMT+03:00 Jean-Michel FRIEDT <jean-michel.friedt@femto-st.fr>:

costas will do the job as long as your measurement bandwidth includes
twice the expected frequency offset, see http://jmfriedt.free.fr/efts_gps.pdf
slide 13.

JM

I am planning to track a signal from a LEO Satellite which transmits
approx. 100 kbps BPSK.
I wonder which blocks should I use since the carrier offset ranges are:
around -50 kHz (beginning of the pass)
around +50 kHz (at the endof the pass)

Possible blocks are:

PLL Carrier Tracking
Costas Loop (using the frequency output port to get the carrier freq. error)

Any other suggestions- Examples?

Please don't offer manually shifting the frequency.(Using Gpredict)

--
JM Friedt, FEMTO-ST Time & Frequency/SENSeOR, 26 rue de l'Epitaphe, 25000 Besancon, France

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