GPS reception (rtl-sdr v3)

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jdsnape
Posts: 2
Joined: Fri Jun 28, 2019 12:35 pm

GPS reception (rtl-sdr v3)

Post by jdsnape » Fri Jun 28, 2019 12:37 pm

Hi,

I'm trying to receive GPS with my SDR and a patch antenna, as per http://sdrgps.blogspot.com/2015/12/acqu ... tlsdr.html or https://gnss-sdr.org/docs/tutorials/gns ... -receiver/

However, it's not getting a lock on any satellites. When I run front-end-cal to get the calibration values I get a different value each time I run it - e.g.

Code: Select all

Sampling frequency =1999986.46 [Hz]
IF bias present in baseband=10668.24 [Hz]


Sampling frequency =1999966.94 [Hz]
IF bias present in baseband=26040.81 [Hz]

Sampling frequency =1999962.02 [Hz]
IF bias present in baseband=29915.58 [Hz]
I'm guessing this can't be right...any ideas what might be causing this behaviour?

Thanks,
Joel

rtlsdrblog
Site Admin
Posts: 2432
Joined: Mon Nov 19, 2012 11:54 pm

Re: GPS reception (rtl-sdr v3)

Post by rtlsdrblog » Mon Jul 01, 2019 4:35 am

I could never get gnss-sdr to work either.

If it's all the same, try this tutorial with RTK-NAVI and gnss-sdrlib https://www.rtl-sdr.com/rtl-sdr-tutoria ... -plotting/. That one works for me, although it is still a bit buggy and the lock is only stable for 20 minutes.

jdsnape
Posts: 2
Joined: Fri Jun 28, 2019 12:35 pm

Re: GPS reception (rtl-sdr v3)

Post by jdsnape » Mon Jul 01, 2019 9:19 am

Thanks, I'll give that a go. Unfortunately, I only have windows running in a VM, so I guess that the virtual USB device may be too slow.

I'm not too fussed about getting a lock for very long, just want to do a POC demo to show it's possible and to be able to inspect the GPS signal at various points.

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