Summary of GPS Error Sources

Typical Error in Meters (per satellite)

                     Standard GPS       Differential GPS

Satellite Clocks        1.5                     0

Orbit Errors            2.5                     0

Ionosphere              5.0                   0.4

Troposphere             0.5                   0.2

Receiver Noise          0.3                   0.3

Multipath               0.6                   0.6

SA                       30                     0


Typical Position Accuracy

Horizontal               50                   1.3

Vertical                 78                   2.0

3-D                      93                   2.8