Interestingly I ran the volk_gnsssdr_profile command from a previous post and then, I could run the LimeMini >20min and it was tracking and logging PVT fine. I then added +3db to all signal source gains and I could acquire in 44s. Now the Loss of lock message only occurs for sats not in view, as it should. Looks good!
Try these in the Conf file for LimeMini:
;SignalSource.gain=40
SignalSource.gain=43
;SignalSource.rf_gain=40
SignalSource.rf_gain=43
;SignalSource.if_gain=30
SignalSource.if_gain=33
Iāve done more testing with this (about a year ago) with the USB LimeSDR since the Mini wasnāt set up to do this easily (at the time - thatās changed now). So thatās my only reference point.
I have seen the issue youāre talking about and the primary reason that it occurs is that we lose acquisition of the signal and you get ājunkā messages in the stream. It comes at either increasing the gain of the LimeSDR (or Mini) or getting a better, higher gain or different positioning, antenna. In the instance I found with testing this, you have to increase the gain of the LimeSDR because the antenna gain was fixed and not changeable (easily) - applying a new gain setting was the easiest way for me to get more consistent results. You mentioned in a later thread that thereās a threat to creating a hardware failure by increasing the gains of the LimeSDR - this would only be an issue if youāre using an antenna or have other gain blocks in the system that would saturate the front end. If thatās the case, then use the gain settings as-is and just try a higher gain antenna. Otherwise, adjusting the gains up in the short run would be your easiest and best short term fix.
Hope this helps - keep us all advised on your progress -
I made some efforts and finally both GNSS-SDR and LimeSDR are installed on ubuntu 18.04 and ready to work. The GNSS-SDR passed My first position fix and SoapySDRUtil --prob find the LimeSDR without any problem. Now Iām trying to feed the LimeSDR with a Spirent simulator and run the GNSS-SDR by using this conf. file https://github.com/gnss-sdr/gnss-sdr/blob/next/conf/gnss-sdr_GPS_L1_LimeSDR.conf
I encounter the following error:
Initializing GNSS-SDR v0.0.14.git-next-419eff942 ā¦ Please wait.
Logging will be written at ā/tmpā
Use gnss-sdr --log_dir=/path/to/log to change that.
OsmoSdr arguments: driver=lime,soapy=1
gr-osmosdr 0.1.4 (0.1.4) gnuradio 3.7.11
built-in source types: file osmosdr fcd rtl rtl_tcp uhd miri hackrf bladerf rfspace airspy airspyhf soapy redpitaya freesrp
FATAL: SoapySDR::Device::make() no match
Trying to fill up 1 missing channel(s) with null source(s).
This is being done to prevent the application from crashing
due to gnuradio bug #528.
Set RX Antenna:
Actual RX Rate: 0 [SPS]ā¦
Actual RX Freq: 0 [Hz]ā¦
PLL Frequency tune error: -1.57542e+09 [Hz]ā¦
Actual RX Gain: 0 dBā¦
Actual Bandwidth: 0 [Hz]ā¦
E0122 12:46:28.883955 29576 pass_through.cc:99] This implementation only supports one input stream
E0122 12:46:28.884174 29576 pass_through.cc:100] 8
E0122 12:46:28.950374 29576 gnss_flowgraph.cc:701] itemsize mismatch: hybrid_observables_gs0:0 using 152, copy2:0 using 8
E0122 12:46:28.950464 29576 control_thread.cc:303] Unable to connect flowgraph
Total GNSS-SDR run time: 0.00653797 [seconds]
GNSS-SDR program ended.
Any idea what is the problem and what should I do? I appreciate itā¦
About the only thing I can think of is that SoapySDR has changed since the time I wrote the article on how to interface the LimeSDR to GNSS_SDR. When I did this (so long ago - maybe 3 years) it all worked per the procedure I wrote. Over time SoapySDR has changed to adapt for other things and it may be due to that - there is an incompatibility now or there are variables in SoapySDR that now exist that didnāt exist then (or removed then to now). The only thing I can recommend is using the SoapySDR version that existed at the time the article was written and work from there. Youād have to start from a complete clean compile, tooā¦Not sure this will help, but I think itās the most likely culpritā¦
@osborn,
Hey I am also trying to capture GPS signals using LimeSDR. Apart from a Bias Tee and a GPS Patch Antenna, did you use any other hardware component? (like a filter or an attenuator) as I have ordered the Bias Tee and is yet to arrive. Thanks in advance!
