Those assisted GPS units can lag by minutes. As to pin-point GPS is only good to so many tens of feet and it can bounce around under certain conditions.
Are you new to GPS and it's limitations? I found a big company tried to use it to track parcels in a building!
How is the GPS-unit in my Acer Iconia A100 supposed to act. Is it pin-point accurate within seconds or does it have a mood of its own?