Saudi Cultural Missions Theses & Dissertations
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Item Restricted Methodology for Selection of Optimal Satellite Constellation for Precise GNSS Positioning(University of Nottingham, 2025-01) Alluhaybi, Abdulaziz; Psimoulis, Panagiotis; Remenyte-Prescott, RasaContinuous advancements in GNSS systems, apart from the broadly used GPS, have led to the development of other satellite systems (Galileo, BeiDou, GLONASS), which have significantly increased the number of available satellites for GNSS positioning applications. However, GNSS satellites’ redundancy and potential poor GNSS satellite signals can negatively affect the GNSS’s positioning speed and accuracy. On the other hand, selecting high-quality GNSS satellite signals by retaining a sufficient number of GNSS satellites can enhance the GNSS’s positioning performance. Various methods have been applied for satellite selection. However, the selected satellites via these methods could be insufficient for precise positioning. These methods were designed to select satellites for Single Point Positioning (SPP) solution with meters level accuracy. This is because these satellite selection methods only consider SPP factors. To choose satellites for precise positioning, new satellite selection method was developed considering Precise Point Positioning (PPP) factors. Various satellite selection methods were investigated and assessed to developed new satellite selection method that fit PPP- satellite selection. To test the performance of the new satellite selection method, several experiments have been conducted. Satellites were selected for various PPP applications: i) static open-sky, ii) kinematic open-sky, and iii) static at multipath conditions. In addition, satellites were selected in all possible subset sizes, i.e., they were selected in subsets with all possible numbers of satellites. According to experiment results, the efficiency of the new satellite selection method was excellent at low multipath environment regardless of PPP modes: static or kinematic. The positioning accuracy of original PPP, using all satellites, was achieved by multiple sizes of selected satellite subsets by the selection method. It was also obtained by selected satellites with different subset sizes. In terms of high multipath environments, the performance of the satellite selection method was less effective. The positioning accuracy of the original PPP was not achieved by the selected satellite subsets although they provided positioning accuracy close to the original PPP with a few satellites. This achievement is quite promising although the new satellite selection method needs further improvement.6 0Item Restricted SMARTPHONE GNSS LOCALIZATION BY DDP AND PPP TECHNIQUES(University of Nottingham, 2020) Alluhaybi, Abdulaziz; Bingley, Richard; Moore, TerryThis dissertation illustrates the performance of a dual-frequency GNSS chip smartphone in GNSS localization in motion. The GNSS localization was performed using the DDP and PPP methods. The smartphone was in motion on a railway and observed the satellites' data for approximately 90 minutes. The smartphone dual-frequency data was processed as single frequency and code measurements due to the limitations of the GNSS processing software and the smartphone antenna. The accuracy of the smartphone DDP and PPP results were at meter level and very similar to each other, such that the difference did not exceed 1 m in all comparison aspects. In contrast, the difference was vast between the smartphone PPP and a geodetic receiver PPP that was running synchronized with the smartphone on the railway; the geodetic receiver PPP provided an accuracy of centimetre which could be possible from the smartphone in the future, but clearly is not yet possible.22 0