Why Is USRP Tx or Rx with GPS Example Not Working?

Updated Sep 4, 2019

Reported In


  • USRP-2950
  • USRP-2952
  • USRP-2954
  • USRP-2955
  • USRP-2930
  • USRP-2932


  • LabVIEW
  • LabVIEW Communications System Design Suite



Issue Details

Now, I am using USRP-2954R for my research. USRP-2954R has a GPS antenna port. When I connect a GPS antenna to the GPS antenna port and run niUSRP EX Tx with GPS.vi or niUSRP EX Rx with GPS.vi, my system is frozen.


The USRP or USRP-RIO device equipped with a GPSDO module takes a lot of time searching for GPS signals. This is the reason why the default value of the Satellite Fix Timeout on the front panel is set to 600 seconds. You can adjust this timeout value by configuring timeout of niUSRP Wait For Lock.vi.
After locking the GPS signal, in niUSRP EX Tx with GPS.vi or niUSRP EX Rx with GPS.vi, USRP or USRP-RIO devices start to generate or acquire RF signals. If the GPS locking process is failed, you need to place the GPS antenna connected to the GPS antenna port of USRP on another place to receive much better GPS signals.