ACTA GEODAETICA ET GEOPHYSICA, vol.49, no.3, pp.343-355, 2014 (SCI-Expanded)
In dam, bridge, railway, sewerage and pipeline projects and the measurement of crustal movements, point positioning must be determined. GPS is the most popular three-dimensional absolute positioning system on all world surfaces; however, the accuracy of GPS measurements is dependent on particular measurements or environmental factors. The main aim of this study is to characterize statistically the effects of selected factors on the individual GPS horizontal and vertical positioning. The factors were the measurement seasons and time of day for the environment aspect and the satellite system for the measurement aspect. A 23 factorial design was utilized to analyze the role of the selected factors in the GPS horizontal and vertical point positioning. The results indicated that the level (2nd season of the year) of measurement season gave the optimum conditions on the accuracy of the horizontal and vertical positioning, this situation could not be obtained for the same level of measurement time and satellite system. Therefore, the measurements factors of horizontal and vertical positioning must be selected and analyzed carefully according to aim of study.