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The objective of this paper is to describe recent progress in the area of the Ground Based Augmentation System (GBAS) s pr_ gnd establishment to ensure aircraft precision approach navigation integrity. In particular, this paper details: (1) the development and testing of a new adaptive binning algorithm for processing GBAS reference station empirical data to account for ranging error non-stationarity; (2) an introduction of a practical empirical method to quantify and compensate for the effects of seasonal variations of ranging error ; and (3) the synthesis of these empirical results with existing theoretical ground-multipath models toward a quantitative establishment s pr_ gnd for GBAS.2. Expanding bin. 3. Sigma estimation.

The brake factor (BF) scales the vehicle's braking force; therefore, the vehicle brake performance variation due to the foundation brake can be attributed to the BF variation. In this work, the BF reduction is considered in the design stage of an S-Cam foundation brake within dimensional properties in order to have stable, predictable and improved vehicle brake performance. First, brake lining wear types were defined and then actuation cam-roller position effects were formulated. Dimensional parameters were varied within certain design-possible ranges to quantify BF variation theoretically. The response surface method (RSM) was used to identify the BF-reduced combination of dimensions within theoretical results. In the meantime, a new testing procedure was introduced and then a new testbed was designed and built to validate relative improvement of BF experimentally without thermal effects on friction. It was investigated that a substantial improvement (22.93 %) on BF could be obtained if appropriate dimensions were selected in the design stage.

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In this paper, an analysis has been performed to quantify and compare the Vertical Protection Levels (VPLs) performances using GPS (Global Positioning System) and GLONASS (GLObal NAvigation Satellite System-GLObalnaya NAvigatsionnaya Sputnikovaya Sistema) satellite navigation systems for the largest Turkish Airport (Istanbul Ataturk Airport-IST). The VPLs are position error bounds computed at aircraft with ensured high navigation performances for initiation of intendent precision aircraft approach and landing in the Ground Based Augmentation System (GBAS). The GBAS, therefore, is an advanced navigation system and designed to provide civil aircraft user with high navigation performances. All defined algorithms in GBAS are built entirely on the GPS positioning solutions. In this study, an alternative constellation of global satellite navigation system GLONASS is considered and its performances are quantified for potential usability in future. In this respect, IST is selected as an implementation site in analysis. Two approaches have been proposed in the quantification of system availability for the given site; a) full constellation with increased elevation mask, b) two satellite outages as a worst-case scenario in the quantification of system availability. Investigations have shown that the GPS could provide superior performance over GLONASS in compliance with the GBAS availability requirements (i.e., exhibits high performance). However, the outcomes are also promising for the prescribed GBAS VPL performance using an alternative constellation (GLONASS) for supporting a precision approach and landing of an aircraft at the IST.