Sounds plausible, but not really. The position fixing firmware is all built into the GPS chipset - probably one of the same chipsets that's used in airborne GPS receivers. Wouldn't be much use if it couldn't get a fix at normal flight speeds, would it? I normally have to hold mine up to the window to get an initial fix in a reasonable amount of time, but after that it's good. Doesn't make any difference if the aircraft is sitting at the gate or in flight at full speed.