本文選題：低軌衛(wèi)星 + Doppler定位��； 參考：《電子科技大學》2014年碩士論文

【摘要】：隨著人們對定位服務(wù)需求的激增,全球?qū)Ш蕉ㄎ幌到y(tǒng)以及其它電磁波定位技術(shù)研究工作方興未艾。全球?qū)Ш蕉ㄎ幌到y(tǒng)雖然具有全天候、高精度等諸多優(yōu)勢并且已在眾多領(lǐng)域中發(fā)揮著關(guān)鍵作用,但是傳統(tǒng)衛(wèi)星導航系統(tǒng)抗干擾能力弱以及普通用戶無法使用被嚴格保密的用于高精度定位的擴頻序列。為了提高某些關(guān)鍵領(lǐng)域中衛(wèi)星定位服務(wù)的獨立性和安全性,本文研究一種融合了低軌衛(wèi)星和全球?qū)Ш蕉ㄎ幌到y(tǒng)的雙模式衛(wèi)星導航系統(tǒng)。雙模式衛(wèi)星導航系統(tǒng)利用低軌衛(wèi)星自身的高動態(tài)特性產(chǎn)生的Doppler頻偏作為測量目標進行定位解算。本文首先闡述Doppler定位解算原理并詳細推導如何利用Doppler頻率觀測值通過最小二乘法和Kalman濾波法來求解用戶位置。接著簡要分析Doppler測量過程中的誤差來源和衛(wèi)星幾何分布對定位精度的影響。同時介紹常見干擾對定位的危害性以及怎樣衡量干擾的大小,并對兩類Doppler測量值平滑方法的性能進行比較。分別使用仿真的低軌衛(wèi)星數(shù)據(jù)和實際GPS數(shù)據(jù)對兩種Doppler定位解算算法進行實驗測試,實驗結(jié)果表明雙模式衛(wèi)星導航系統(tǒng)中采用的Doppler定位方法可使用戶獲得十到幾百米范圍的定位精度。本文重點研究了適合于雙模式衛(wèi)星導航系統(tǒng)的Doppler接收機跟蹤環(huán)路設(shè)計方法,旨在使新設(shè)計的接收機跟蹤環(huán)路既能夠在低軌衛(wèi)星高動態(tài)條件下順利工作同時還能有效減少初始捕獲單元的計算量。文章首先介紹了一種新型頻率鑒別器,然后給出了傳統(tǒng)基于Kalman濾波的鎖相環(huán)的帶寬和頻率估計誤差計算公式,并分析其性能。最后使用新型頻率鑒別器改進傳統(tǒng)自適應(yīng)兩階段Kalman濾波環(huán)路,提出了一種鎖頻環(huán)輔助的Kalman濾波跟蹤環(huán)路設(shè)計方案。利用實際采集的GPS數(shù)據(jù)和模擬低軌衛(wèi)星數(shù)據(jù)對新型跟蹤環(huán)路的仿真測試結(jié)果表明此方法不僅能夠在高動態(tài)環(huán)境中正常工作,而且還能夠容忍更大的初始頻率偏差從而大幅度降低捕獲的精度要求。
[Abstract]:With the rapid increase in demand for positioning services, the research of global navigation and positioning system and other electromagnetic wave positioning technology is in the ascendant. Although the Global Navigation and Positioning system has many advantages, such as all-weather, high-precision and so on, it has played a key role in many fields. But the traditional satellite navigation system has weak anti-jamming ability and ordinary users can not use the strictly secret spread spectrum sequence for high-precision positioning. In order to improve the independence and security of satellite positioning service in some key fields, this paper studies a dual-mode satellite navigation system which combines Leo satellite and global navigation positioning system. The dual-mode satellite navigation system uses the Doppler frequency offset generated by the high dynamic characteristics of the Leo satellite as the target to locate and calculate. In this paper, the principle of Doppler location solution is introduced, and how to use Doppler frequency observations to solve user's position by least square method and Kalman filter method is deduced in detail. Then, the error sources and the influence of satellite geometry distribution on the positioning accuracy are analyzed briefly. At the same time, the harmfulness of common interference to localization and how to measure the magnitude of interference are introduced, and the performance of two kinds of Doppler measurement smoothing methods are compared. Using simulated Leo satellite data and actual GPS data, two Doppler positioning solution methods are tested. The experimental results show that the Doppler localization method used in the dual-mode satellite navigation system can achieve the positioning accuracy in the range of 10 to several hundred meters. This paper focuses on the design method of Doppler receiver tracking loop suitable for dual-mode satellite navigation system. The new designed receiver tracking loop can not only work smoothly under the high dynamic condition of Leo satellite, but also reduce the computation of the initial acquisition unit effectively. In this paper, a new frequency discriminator is introduced, then the calculation formulas of bandwidth and frequency estimation error of traditional phase-locked loop based on Kalman filter are given, and its performance is analyzed. Finally, a new frequency discriminator is used to improve the traditional adaptive two-stage Kalman filter loop, and a design scheme of the frequency-locked loop aided Kalman filter tracking loop is proposed. The simulation results of GPS data and simulated Leo satellite data show that this method can not only work normally in high dynamic environment, but also in high dynamic environment. Moreover, it can tolerate larger initial frequency deviation and greatly reduce the precision requirement of capture.
【學位授予單位】：電子科技大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN967.1
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本文編號：2078527