The accuracy of a position determined by using a GPS receiver is limited by the accuracy of the GPS signal itself. The US government controls the precision of the GPS signals sent from the GPS satellite constellation. It varies from day to day, and the following graph shows historically, how precise the GPS position information is.
Raveon’s GPS transponders utilize the WAAS signal, so accuracies of 2-3 meters are possible. Laboratory tests with the M7 series of GPS transponders confirm that this is possible, but typically, the accuracy is in the 3-5 meter range.
If the GPS transponder is located indoors, or if there are very tall buildings near the transponder, the accuracy will be degraded due to multipath of the GPS signal.