Originally Posted by
BAengineer
Are you sure about that? - I am currently sitting in Missouri and my cellphone has no problem using GLONASS with GPS switched off - its currently using 4 of their satellites..
That certainly used to be the case, because the US authorities were concerned about an accurate positioning system over the US that they couldn't control. So they didn't license reception of the over there and manufacturers were supposed to block reception there. How strictly that was followed in practice I don't know, but certainly the EU are still negotiating an agreement for Galileo. If your phone can receive Glonass, that's good.
Incidentally, which phone are you using? Most don't allow allow you to select which GNSS to use - they are all on or off..