2. While GPS capabilities have improved over time, the use of GPS receivers in cell phones are far from perfect, in the case of movement its better to stand still when trying to receive a GPS fix, of course once you're coordinates are locked into place you can walk around, go for a jog, heck you can even drive down the highway with pinpoint accuracy in most cases. Remember that you aren't simply locking in one satellite, but rather in some cases up to 20 separate signals, if you move around like crazy its going to be harder for those signals to triangulate your exact location.