A lot of these devices only have AGPS (assisted GPS) which is based on cell phone towers, only good for ground based use. Best to use a bluetooth connected real GPS reciever.
A/GPS is a real GPS, it uses the cell locations in order to improve the lock time before the full almanac is available. Away from cell towers it just takes longer to lock on. The older the almanac the longer it takes.
A bit of research before repeating old wives tails as fact perhaps?