الفهرس | Only 14 pages are availabe for public view |
Abstract This thesis tries to enhance the performance of Precise Point Positioning technique to obtain higher precision at a faster convergence time. Consequently, a judicious modeling of all parameters and a careful selection of the correction models is accomplished to reduce the impact of error propagation on the precision of parameters estimation. Also, this thesis tries to improve single, dual and triple frequencies PPP for both static and kinematics modes using multi-constellations GNSS. Therefore, to enhance single frequency PPP, a local ionospheric model for Egypt is developed with temporal resolution of two-hours and spatial resolution of 0.5{u00B0} and 0.5{u00B0} in longitude and latitude, respectively. The performance of the developed Egyptian Ionosphere Model (EIM) is verified through the positioning accuracy of Single Frequency Precise Point Positioning SFPPP, for static and kinematic positioning modes in comparison with the Klobuchar and Global Ionosphere Maps GIM. While for dual and triple frequencies, accurate PPP models other than conventional un-differenced ionosphere free are developed to enhance the positioning accuracy. Both Multiple Ambiguity Datum (MAD) and Between-Satellite-Single-Difference (BSSD) ionosphere-free linear combinations of Global Navigation Satellite Systema pseudo-range and carrier phase measurements are processed using precise clock and orbital products obtained from International GNSS service Multi-GNSS Experiment IGS (MEGX). The performance of the developed PPP techniques is assessed in both static and kinematic modes in comparison with the traditional un-differenced GNSS PPP model |