Investigation about LAAS Signal-in-Space Integrity

• Main Authors: Shi-LinYe, 葉時霖
• Other Authors: Fan-Ren Chang
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/18153143822180018891

碩士 === 國立臺灣大學 === 電機工程學研究所 === 89 === This thesis focuses on the Local Area Augmentation System (LAAS) Signal-in-Space (SIS) integrity. The concept of Protection Level is one part of SIS integrity algorithms. It is used to overbound the Navigation System Error (NSE) and to replace the NSE being compared with some specified Alert Limits (AL). Based on some assumptions made by RTCA, the protection level should be formulated carefully to meet the SIS integrity requirements. One of these assumptions is that the ground processing function and the pseudorange correction errors are assumed mutually independent. Then, the pseudorange correction errors can be modeled as Gaussian distributed random variables. However, it is shown that the probability density functions of the pseudorange correction errors are not Gaussian if the ground processing function is performed. Therefore, the protection level algorithms should be modified. To simplify the protection level calculation, the idea of Gaussian overbound is introduced to bound the pseudorange correction errors. Thus, through the obtained Gaussian probability density functions, the protection level then can be determined. In this thesis, the values of protection level are simulated by using MATLAB.