Here is the proof:
imagen.png
Many many thanks to everyone!
David
El mar, 28 feb 2023 a las 18:27, David Dima (<daviddimavd@gmail.com>)
escribió:
All right guys, I got it, it works now. The central frequency
should have been 1911.795 MHz instead of 1189.5MHz. The final
configuration results as follows:
imagen.png
imagen.png
Thank you very much to everybody!
Best regards,
David
El mar, 28 feb 2023 a las 18:17, Marcus Müller
(<mmueller@gnuradio.org>) escribió:
Hi David,
please stay in the habit of keeping the mailing list in CC!
Can you please write this email to the mailing list?
Thanks,
Marcus
On 28.02.23 17:55, David Dima wrote:
> Hi Marcus,
> According to Galileo's signal plan
> (https://gssc.esa.int/navipedia/index.php/Galileo_Signal_Plan
>
<https://gssc.esa.int/navipedia/index.php/Galileo_Signal_Plan>),
E5b bandwidth is 25MHz,
> but to save memory and resources, I sample at 20MHz because
I demonstrated by testing that
> is enough to process the signal without losing information.
>
> Regarding the Xlating filters: if I tune the USRP in the
middle of the signals (1164MHz +
> (1215-1164)/2)MHz = 1189.5MHz) , then I have to shift the
spectrum +- 15.345 (According to
> Daniel: "The band plan you posted is slightly wrong. The
distance between the
> AltBOC sidebands and the centre frequency is 15 * 1.023
MHz.") to be able to record at
> 25MHz each band (E5a and E5b). I am trying to do the following:
> imagen.png
> Kind regards,
> David
>
> El mar, 28 feb 2023 a las 17:25, Marcus Müller
(<mmueller@gnuradio.org
> <mailto:mmueller@gnuradio.org>>) escribió:
>
> Hi David,
>
> On 28.02.23 17:17, David Dima wrote:
>> Dear Marcus, all
>> Thank you for your response. You are right, I will try
to better explain the problem:
>>
>> Well, when I record the signals separately (for example
E5b) as shown in the below
>> picture, and after that I try to process the file
containing the IQ samples by means
>> of GNSS-SDR free-tool, I can parse the messages to
generate ephemeris, almanac or
>> Rinex files. Even if E5b bandwidth is 25MHz, it works
sampling at 20 MHz.
>> imagen.png
>
>
> You're losing 1/5 of the relevant spectrum. That doesn't
mean it *can't* work, it's
> just unnecessarily bad – honestly, **why** are you using
a sampling rate that's not
> fit to represent the *full* signal? Can you please state
*reasons*?
>
>
>>
>> The issue comes when I try to record both signals at
the same time. Taking into
>> account the suggestions Jim, Daniel and you have given
me in the forum, I have made
>> a couple of changes in the program resulting in:
>> imagen.png
>> Now, at least I think I am closer to getting what I
need but I am not sure if there
>> are more mistakes in the flowgraph. So, I have tried to
record the signals according
>> to the above flowgraph but after that I still cannot
read any signal from the
>> satellites whereas if I record them separately I can.
>
> This makes no sense at all. Where do your "Center
Frequencies" in the Freq.-Xlating
> filters come from?
>
> Best regards,
> Marcus
>