RF Measurement Devices

GNSS and USRP transmission

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 (no satellites in Skyview, no position lock, or date/time change) on my GNSS receiver. 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?

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)