1.2bis Accuracy

for a standard GPS equiped with PPS:
- horizontal : 22 meters
- vertical : 27.7 meters
- time : 200 nanoseconds
how to refine accuracy ?
- differential GPS: network of known reference points
- ( → accuracy < 1 m)
- geodesics recievers: use two signals produced by the same satellite ( → accuracy < 1 cm)

for a standard GPS equiped with PPS: