【摘要】：隨著全球定位系統(tǒng)（GPS）的普遍應(yīng)用，干擾抑制成為了研究熱點(diǎn)。信號(hào)的干擾因素有很多，尤其是在具有許多高樓大廈、橋梁等建筑物的城市環(huán)境中，存在不同程度的多徑誤差。多徑誤差是GPS系統(tǒng)測量中最主要誤差來源之一，其不能像電離層誤差和對(duì)流層誤差等誤差源一樣，可以通過差分技術(shù)或建模來消除，因此抑制多徑誤差成為現(xiàn)在全球衛(wèi)星導(dǎo)航系統(tǒng)的熱點(diǎn)和難題。本文的主要工作如下： 在概述GPS系統(tǒng)基本組成和GPS信號(hào)的結(jié)構(gòu)與特點(diǎn)的基礎(chǔ)上，重點(diǎn)介紹了GPS接收機(jī)跟蹤環(huán)的基本工作原理，并利用卡爾曼濾波器仿真實(shí)現(xiàn)了載波跟蹤環(huán)中的環(huán)路濾波器。 在分析了GPS系統(tǒng)中測量誤差主要來源和特點(diǎn)的基礎(chǔ)上，，重點(diǎn)研究多徑誤差的來源和特點(diǎn)；基于多徑信號(hào)的一般數(shù)學(xué)模型，重點(diǎn)研究了多徑信號(hào)對(duì)GPS跟蹤環(huán)的影響。 通過分析對(duì)比了窄相關(guān)技術(shù)、Strobe相關(guān)器技術(shù)和ELS（Early Late Slope）多徑抑制技術(shù)等經(jīng)典的基于鑒別器函數(shù)的多徑抑制算法，針對(duì)這些算法的性能受接收機(jī)前端預(yù)相關(guān)帶寬以及噪聲的影響，提出了一種基于隨機(jī)Hough變換（RHT，Randomized HoughTransform）估計(jì)相關(guān)峰兩邊斜率的多徑抑制算法，并通過仿真分析對(duì)比了ELS多徑抑制技術(shù)和基于RHT的斜率估計(jì)多徑抑制算法的性能。 通過對(duì)基于最大似然估計(jì)的多徑延遲鎖定環(huán)的仿真分析，針對(duì)MEDLL（MultipathEstimating Delay Lock Loop）算法性能受到噪聲和相關(guān)器個(gè)數(shù)的影響，提出一種基于Kalman濾波改進(jìn)的MEDLL算法，并通過仿真對(duì)比分析了該算法與MEDLL算法的性能。 基于擴(kuò)展卡爾曼濾波（EKF，即Extended Kalman Filter）的基本原理，設(shè)計(jì)并仿真了基于EKF的GPS跟蹤環(huán)，利用動(dòng)態(tài)估計(jì)得到輸入信號(hào)各參數(shù)，達(dá)到抑制多徑的目的。
[Abstract]:With the widespread application of global positioning system (GPS), interference suppression has become a research hotspot. There are many interference factors, especially in the urban environment with many high-rise buildings, bridges and other buildings, there are multi-path errors in varying degrees. Multipath error is one of the most important sources of error in GPS measurement. It can not be eliminated by difference technique or modeling like ionospheric error and tropospheric error. Therefore, the suppression of multipath error has become a hot and difficult problem in the global satellite navigation system. The main work of this paper is as follows: on the basis of summarizing the basic composition of the GPS system and the structure and characteristics of the GPS signal, the basic working principle of the GPS receiver tracking loop is introduced emphatically. The loop filter in carrier tracking loop is simulated by Kalman filter. Based on the analysis of the main sources and characteristics of the measurement errors in the GPS system, the source and characteristics of the multipath errors are studied, and based on the general mathematical model of the multipath signals, the influence of the multipath signals on the GPS tracking loop is studied emphatically. The classical multipath suppression algorithms based on discriminator function, such as narrow correlation technique, Strobe correlator technology and ELS (Early Late Slope) multipath suppression technique, are analyzed and compared. For the performance of these algorithms is affected by the pre-correlation bandwidth and noise of the receiver front end, a multipath suppression algorithm based on random Hough transform (RHT,Randomized HoughTransform) to estimate the slopes of the correlation peaks is proposed. The performance of the ELS multipath suppression technique and the slope estimation multipath suppression algorithm based on RHT are compared by simulation. Based on the simulation analysis of multipath delay locking loop based on maximum likelihood estimation (MLE), an improved MEDLL algorithm based on Kalman filter is proposed to improve the performance of MEDLL (MultipathEstimating Delay Lock Loop) algorithm due to the influence of noise and correlator number. The performance of this algorithm is compared with that of MEDLL algorithm by simulation. Based on the basic principle of EKF, (Extended Kalman Filter), the GPS tracking loop based on EKF is designed and simulated. The parameters of the input signal are obtained by dynamic estimation, and the multipath suppression is achieved.
【學(xué)位授予單位】：華東交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：P228.4

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本文編號(hào)：2467747