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Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/35705

Title: 基於分散式預濾波器追蹤迴路之超緊密GPS/INS整合導航系統
Design of the Tracking Loop Using the Decentralized Pre-filters for the Ultra-Tightly Coupled GPS/INS Navigation System
Authors: Chi-Fan Yang
楊棋帆
Contributors: NTOU:Department of Communications Navigation and Control Engineering
國立臺灣海洋大學:通訊與導航工程學系
Keywords: 整合導航系統;向量追蹤迴路;預濾波器;無跡卡爾曼濾波器;模糊邏輯自適應系統
Integrated navigation system;Vector tracking loop;Pre-filter;Unscented Kalman filter;Fuzzy logic adaptive system
Date: 2012
Issue Date: 2013-10-07T02:58:04Z
Abstract: 追蹤處於高動態情況下的GPS訊號,對於接收機的設計者來說是一個具有挑戰性的工作,單一接收機的系統,當載體處於高動態之情況時,通常會使得觀測量的品質降低,因此,為了解決此問題,常見的方法為透過慣性導航系統(Inertial Navigation System, INS)的輔助。 在許多的研究中,都提出了利用無跡卡爾曼濾波器(Unscented Kalman Filter, UKF)設計超緊密GPS/INS整合導航系統,在這樣的架構下,INS的誤差模型扮演著相當重要的角色,在本文當中也會分析GPS的觀測量正交相(I, in-phase)、四分相(Q, quadrature)與INS推算出的狀態(速度和位置)之間的關係。 在超緊密GPS/INS整合導航系統的架構中,利用濾波器設計追蹤迴路,在先前的研究中,從相關器(correlator)輸出的I/Q訊號直接做為後端導航濾波器之觀測量,而本文所提出的方法,相關器輸出的I/Q訊號會先經過一批濾波器,本文稱之為預濾波器(pre-filter),每個通道都會有一個預濾波器,透過此濾波器可以估測出每顆衛星訊號的電碼相位誤差(code phase error)以及都卜勒頻率誤差(Doppler frequency error),以往此預濾波器的設計通常都是使用擴展型卡爾曼濾波器(Extended Kalman Filter, EKF),但由於GPS訊號的觀測量模型屬於高度非線性,為了提升估測的精度,本文將選擇在非線性的狀況時有較好表現的非線性濾波器來設計。最後,為了改善訊號在高動態時,都卜勒頻率誤差會有劇烈的變化,因此,在預濾波器內加入模糊邏輯自適應(Fuzzy logic adaptive)的架構,藉此使得濾波器參數有較好的彈性,減少因為高動態所產生的估測誤差。
Tracking dynamics on the GPS signal is still a big challenge to the receiver designer as the operating conditions are becoming more volatile. Optimizing the stand-alone system for high dynamics generally degrades the accuracy of measurement. Therefore, the GPS is aided with inertial navigation system (INS) to address this issue. Several researchers proposed an Unscented Kalman Filter design approach for the ultra-tight GPS/INS integration. Based on this structure, INS error models are discussed. Through analyzing the relationship between GPS (I&Q) measurement and INS (position and velocity) states I/Q estimate method is proposed. Traditionally, the signals from each satellite are processed independently. The ultra-tight GPS/INS integration system uses a bank of pre-filters to estimate code delay error and Doppler frequency error for each satellite. This vector-based method can perform better than traditional methods. However, the changes of Doppler frequency are violent in the high dynamic situation. For improving the performance of pre-filter, this paper employed the Fuzzy Logic Adaptive UKF. Based on the proposed structure, the parameters of UKF will be tuned more smartly. Accordingly, the effect of high dynamic can be reduced.
URI: http://ethesys.lib.ntou.edu.tw/cdrfb3/record/#G0019967026
http://ntour.ntou.edu.tw/handle/987654321/35705
Appears in Collections:[通訊與導航工程學系] 博碩士論文

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