Is it the GPS or no 3G data available at that location???
Data is needed for the navigation app to work properly with GPS.
What app are you using? Google navigation app or other app?
GPS module on Galaxy Nexus sucks. A few weeks ago a lot of GNex phones around the world on Jelly Bean were affected by the GPS glitch (my phone included) The GPS was always a weak point of Samsung devices, I must admit though GPS on my GS2 Skyrocket used to work perfectly fine untill it got updated to ICS.
