الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Among currently used Global Navigation Satellite Systems (GNSS), the Global Positioning System (GPS) from the USA and the Russian GLONASS system are the best known, and currently fully operational. Multiple factors can effect on the GNSS technique in surveying such as level of required accuracy, suitability of equipment, time, available budget, type of measurement techniques and satellite availability. Recently, static and Real-Time Kinematic (RTK) surveying using GNSS are the common method used for both cadastral and engineering surveying in Egypt. Despite the benefit of using GPS system, no standard specifications and/or guidelines was performed in surveying firms across Egypt. Thus, an effort was made in the present study to estimate/establish such relationship by applying Quality Assurance (QA) and Quality Control (QC) on the GNSS surveying firms. A closed questionnaire was designed and distributed to different categories of surveying specialists. The questionnaire was designed to cover the main points under investigation in the GNSS surveying. from the results of questionnaire, the responses on the GNSS surveying from the professional staff and field surveyors in Egypt show some similarity that is mean there have a quality control; but, such responses did not follow most of the current specifications. In addition, the general system used to determine the positioning in Egypt is GPS, whereas the GNSS is the main system used worldwide, which might lead to a lack of accuracy quality in the survey works in Egypt. According to the results of a questionnaire, it is revealed that there are some problems which affect the quality management system and hence the positioning accuracy of static or RTK observation. Therefore, a practical study is done to set the specifications and guidelines which are an important step of quality planning to achieve high accuracy according to the capabilities of receivers’ antenna available in each surveying firm. The first problem is the multipath error is the most common type of error which affects the accuracy of positioning. Therefore, by the results of practical study was conducted to indicate the optimum time of observation with different satellite systems and with different signals (L1 only, L1+L2 and L1+L2+L5) on any point for open sky, obstruction from one side and obstruction from two sides. The second problem is the effect of phase center variations with non-identical antennas with different baselines lengths is based on the results of the main purpose of the present study. Therefore, by the results of practical study can be concluded that using non-identical receivers for the same project deteriorates the accuracy. Consequently, it will negatively affect the quality management system.