lesto:
gps have 2 meter radius precision AND normally 1 or 5 Hz output... i don't think it is enough.
Low-cost GPS have up to 10Hz sampling rate. The precision is about 2 meters (WAAS/EGNOS-enabled), but -if I'm not wrong- that's not affecting the results. If it's 2m, it will be also 2m here (sample #1) and 2m there (sample #2). So the results will be -almost- the same...