Global Positioning System Errors Magnitude And Effects

Abstract

The error sources in GPS and inconsistencies between reference datum of the system and physical reality more or less disturb its performance as a geodetic measurement technique. Today numerous scientific studies are carried on to develop applicable solutions to eliminate or minimize the weakness of this very practical and precise positioning technique. In this study methods to reduce the errors that affect the accuracy of the estimated position derived from GPS measurements, namely:- the Satellite dependent errors, Propagation dependent errors and receiver dependent errors are fully discussed. It is found that the Ephemeris data errors has a magnitude of 1-5 meters, the clock Drift 0–1.5 meters, the selective Availability 0–70 meters, the ionospheric delay 0–30 meters, the tropospheric delay 0–30 meters and the multipath effect is 0–1 meters. When differential techniques are applied the mentioned errors are mostly removed except multipath.