碩士 / 國立臺灣海洋大學 / 通訊與導航工程學系 / 104 / The Global Positioning System (GPS) signals are quite vulnerable to different types of interference since they are very weak once received on the earth surface. Spoofing is a deliberate interference that aims to coerce global navigation satellite system receivers into generating false position/navigation solutions. Spoofing sources also can increase the power content of structural signals within the GPS frequency bands and this feature can reveal the presence of spoofing interference before the despreading process of the receiver. The GPS system is generally lack of immunity against spoofing attack. Spoofing sources can effectively disrupt a GPS receiver during the acquisition phase by generating multiple false correlation peaks and increasing the noise floor. Such deceptive correlation peaks can mislead the GPS receiver into acquiring the spoofer generated signals rather than the authentic signals. This thesis presents the investigation of important topics on the design of anti-spoofing countermeasures to detect and mitigate spoofing attacks for the GPS receivers. One is signal strength analysis at signal processing level. The main focus of this part is on assessment of the reduced effectiveness of the GPS spoofer countermeasure during acquisition where the GPS receiver utilizes discrimination. The threshold method in acquisition is used and the successful probability of anti-spoofing/spoofing is involved. The important issues to be exploited include the influence of input SNR, spoofing signal amplification factor, coherent integration time and false alarm on successful probability of anti-spoofing/spoofing. The other is M-estimation techniques for anti-spoofing GPS navigation. In this approach, the extended Kalman filter(EKF) is modified using the weight matrix of robust M-estimator, which is improved to decrease the computational complexity with enough navigation accuracy. Simulations of the proposed M-estimator based extended Kalman filter show that it can effectively eliminate the influence of spoofing signal to the navigation solution accuracy.
| Identifer | oai:union.ndltd.org:TW/104NTOU5300031 |
| Date | January 2016 |
| Creators | Wu, Jung-Hsiang, 吳榮祥 |
| Contributors | Jwo, Dah-Jing, 卓大靖 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 62 |
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