الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
1:-Introduction: -Positioning using low-cost single-frequency GPS receivers deliver an economical Solution, but these receivers are subject to biases leading to degradation of the accuracy required. Factors contributing to degradation in the accuracy of low-cost systems are ionospheric and troposphere delay, orbital error, satellite and receiver clock error, multipath, and measurement noise. These errors change the ambiguity resolution process, and result in less accurate positioning solutions. However, with the recent hardware improvements, measurement noise is now almost negligible. Ionospheric delay has been eliminated with the availability of global or local ionospheric maps produced by various organizations (e.g., International GNSS Service (IGS).Finally, accurate results for position can be achieved by using single frequency receivers.2:- Research scope: -This research aims to assessment of using single frequency GPS receivers in establishment of geodetic networks, also the possibility of using single frequency receivers in differential kinematic applications. 3:- Research objective: -This thesis will investigate methods of mitigating the ionospheric effect on single frequency data and the effect of using global ionospheric maps (GIM) and final precise orbits produced by IGS in improvement the accuracy of relative single frequency positioning in normal baselines. Also, it investigates the possibility of using, low cost, single frequency receivers in establishment the geodetic control networks and Study and evaluate the effect of baseline length on the accuracy of single frequency relative point positioning. The ultimate goal of the thesis is to demonstrate the accuracy and the reliability of single-frequency in static and kinematic relative positioning over normal baselines lengths up to 58.3 km.4:- Steps Study: -In this research, singleand dual-frequency GPS receivers were used to collect static data for the same networks. Data were collected at several locations with different baseline lengths using a sampling rate of 1 Hz. To test the applicability of the proposed low-cost system in the kinematic mode, kinematic data were also collected. The same receivers were used for the static and kinematic data. Then the processing of dual and single frequency data was done by using Trimble Total Control (TTC) and HDS 2003 processing software. Loop Closing error for the different triangular networks and coordinates discrepancies for different baselines lengths were computed to evaluate the variation between dual and single frequency GPS results.5:- Summary of Study:- Accuracy within millimeter- level was demonstrated for static baselines up to 35 km using Nexteq T5 single frequency GPS receiver. Also, Single frequency receivers can be used for differential kinematic applications which require centimeter- level accuracy for horizontal positioning and decimeter-level accuracy for vertical position for baselines up to 26 km.