[Gnss-sdr-developers] Help with collecting GNSS signals by using GNSS-SDR and USRP N210

[Katarina R. <kr...@fe...>]

Hi,

we have problem with collecting GNSS signals for GNSS spoofing by using USRP N210 (daughterboard UBX-40), active GNSS antenna (GPSGlonass-36-N-GA<https://www.scribd.com/document/511736732/Datasheet-2-Antena-Gps-Gpsglonass-36-n-Ga>) and GNSS-SDR.
Firstly, we followed all steps from GNSS-SDR configuration page and we successfully got the position fixes with downloaded file of raw signal samples as at the link<https://gnss-sdr.org/my-first-fix/>.
Afterwards, we tried to get the position fixes with active GNSS antenna but unsuccessfully. We set all the parameters as at the instructions at the link<https://gnss-sdr.org/conf/> and ran 'my_GPS_receiver.conf' file. As the result, we got printed 'D' (please see screenshots 1 and 2 attached). We tried to solve this problem by following the instructions at ETTUS page<https://kb.ettus.com/USRP_Host_Performance_Tuning_Tips_and_Tricks#Thread_Priority_Scheduling> but nothing worked in our case.

Then, we tried to set the sampling frequency to 2MHz and there was no printed 'D' after running the conf file. However, we didn't get the position fixes and we only got 'Loss of lock in channel' (screenshot 3).  We searched for the solution and we wonder if missed something or we do not have all necessary equipment (we saw that bias-tee is needed for some daughterboards).

We would be thankful if you could help us with our problem.

Thank you in advance and best regards,
Katarina Radoš and Marta Brkić