GNSS Test Toolkit 3.0 USRP Transmission

[binarystar105]

Hello 

I am working with USRP and GNSS Test Toolkit 3.0 to generate GNSS signals. As I transmit the generated signal through the USRP, I have difficulty getting anything on my Garmin/GNSS device(no satellites/no lock). What might be wrong, especially about the generation parameters/configuration? What should be the TX power level? Are there any other aspects that I need to consider? 

I will be looking forward to hearing from you. Best regards,

[mourad_FAKHFAKH]

Hi, 

At this stage, the responses you would get would be pure guessing as we know very little about the setup you are using 

1-Please provide a description of your hardware setup and how you are using the GNSS Test toolkit (Testbed, GNSS device, any RF attenuators and cables ..) 

2-You have the ability to use your USRP as a GNSS receiver with the GNSS SDR Software tool . If you are able somehow to record some IQ samples, you may be able to troubleshoot with the GNSS SDR Software.

3- Please provide a clear configuration of the GNSS test toolkit you are using so that we can help you troubleshoot. 

[binarystar105]

Hello, thanks for your response. 

Description of hardware setup:

I am using NI USRP-2974 with the default streaming project, where I read the GNSS binary file created using GNSS toolkit 3.0 and transmit the IQs at a rate of 10MS/s (read from the binary file) at a center frequency of 1602 MHz using an omni antenna which is appropriate for the L band. All other USRP TX settings are at default values. I have tried attenuators ranging from -50 dB to -90 dB. My GNSS receiver/test device is a surveying GNSS tablet with a GNSS antenna.

Configuration of the GNSS test toolkit:

I have used niGLONASS Write Waveform to File (Simple, Automatic Mode).vi from the GNSS toolkit 3.0 with the default values (including the almanac and ephemeris files provided with the toolkit)

Looking forward to hearing from you. Regards,