Re: Galileo E5a and E5b bands simultaneously receiver with GRC

Sure, you need to filter, and frequency-shift, and potentially resample.
What's the sampling rate your GNSS software expects?

Best regards,
Marcus

On 2/14/23 17:10, David Dima wrote:
> Hi Marcus,
>
> Thank you for your very prompt response. I have changed that but it
> still does not work. Do you know if it is possible to separate the two
> bands after the UHD: USRP block?
>
> David
>
> El mar, 14 feb 2023 a las 16:54, Marcus Müller (<mueller@kit.edu>)
> escribió:
>
> H David,
>
> that makes no sense – from the figure, you would need to capture
> 50 MHz
> of bandwidth. So, you will need at least that as sampling rate.
>
> Your Bandwidth setting makes no sense, either, unless it's less
> than the
> sampling rate (in general, just leave that field empty, and UHD will
> choose an appropriate filter for your sampling rate).
>
> So, that will have to change.
>
> Best regards,
> Marcus
>
> On 2/14/23 16:30, David Dima wrote:
> > Hello,
> > I am trying to *record simultaneously *the Galileo IQ *E5a and E5b*
> > signals with GNU Radio Companion (GRC) as follows:
> >
> >
> >
> > The UHD: USRP Source main parameters are set up as follows:
> > - Sampling rate: 20.5Msps
> > - Channel bandwidth: 50MHz
> > - Central frequency: 1191.795MHz
> > - Number of channels: 1 ( Since USRP 2190 model has only 1 local
> > oscillator, it will not be possible to use 2
> simultaneously channels
> > for receiving)
> >
> > The IQ samples are stored in a file for further processing using a
> > configuration file of the GNSS-SDR tool.
> >
> > I manage to process and read the E5a signal correctly, but it
> does not
> > work for E5b. So I think the issue comes from the way I
> > implemented the receiver in GRC.
> >
> > The question is, if it is necessary to do any intermediate
> processing
> > of the signal in GRC to accomplish the aforementioned task.
> >
> > Many thanks in advance,
> >
> > David
>