Cellphone-specifically, I've had a Motorola phone that had a GPS receiver, but was horrendously bad at it - it could take it around 5 minutes to get a fix where my standalone Bluetooth receiver would manage in less than a minute.
Why are you declaring failure after a fixed timeout anyway? Why not, after a reasonable time has passed (say, a minute), display a message to the tune of "GPS fix still not available; but I'm still trying" with a possibility to cancel at any time if the user is fed up? What do you expect the user to do with the failure message you're proposing to give him?