發(fā)布時(shí)間：2018-04-26 07:33

  本文選題：全球定位系統(tǒng) + 高動(dòng)態(tài)�。� 參考：《上海交通大學(xué)》2013年碩士論文

【摘要】：全球定位系統(tǒng)（GPS, Global Positioning System），是目前國(guó)際上最完善的衛(wèi)星導(dǎo)航定位系統(tǒng)，可以為地球表面絕大部分地區(qū)（98%）提供連續(xù)實(shí)時(shí)的三維坐標(biāo)信息、速度信息與授時(shí)服務(wù)。近年來(lái)，基于GPS的導(dǎo)航設(shè)備運(yùn)用越來(lái)越廣泛，在未來(lái)有著廣闊的發(fā)展前景。GPS信號(hào)跟蹤是在已經(jīng)完成信號(hào)捕獲的基礎(chǔ)之上，實(shí)時(shí)地跟蹤碼相位變化和載波多普勒變化，實(shí)現(xiàn)接收機(jī)本地復(fù)現(xiàn)信號(hào)同輸入信號(hào)的準(zhǔn)確同步的過(guò)程，是GPS信號(hào)處理最重要的組成部分之一。傳統(tǒng)的GPS信號(hào)跟蹤環(huán)路采用延遲鎖定環(huán)（Delay Locked Loop，DLL）和鎖相環(huán)（PhaseLocked Loop，PLL）來(lái)實(shí)現(xiàn)碼相位跟蹤和載波跟蹤，但是在高動(dòng)態(tài)或是微弱信號(hào)的條件下，傳統(tǒng)的跟蹤環(huán)路由于其固有缺陷，性能大大下降。 首先在高動(dòng)態(tài)的環(huán)境下，由于GPS信號(hào)的多普勒頻移過(guò)大，傳統(tǒng)跟蹤環(huán)路很容易失鎖，跟蹤精度也不夠理想。本文采用了包含多普勒頻移與碼相位誤差的二維觀測(cè)相關(guān)器組，并通過(guò)基于列文伯格-馬夸爾特方法優(yōu)化的迭代擴(kuò)展卡爾曼濾波算法，使跟蹤環(huán)路在碼相位與載波頻率初始捕獲誤差較大的情況下，依然能夠快速而準(zhǔn)確地收斂，并成功解調(diào)出導(dǎo)航信息。仿真結(jié)果顯示，利用新的GPS信號(hào)跟蹤模型能夠高質(zhì)量地完成加速度為150g的高動(dòng)態(tài)GPS信號(hào)的跟蹤。 其次，針對(duì)傳統(tǒng)跟蹤算法對(duì)微弱GPS信號(hào)跟蹤困難、容易發(fā)散的缺陷，提出了一種新的跟蹤算法。采用自適應(yīng)卡爾曼濾波，減輕噪聲對(duì)信號(hào)的影響，并通過(guò)列文伯格-馬夸爾特優(yōu)化方法，進(jìn)一步提高自適應(yīng)卡爾曼濾波算法的穩(wěn)定性和收斂速度。仿真結(jié)果顯示，利用新的算法對(duì)載噪比低至21dB-Hz的微弱GPS信號(hào)取得了良好的跟蹤精度和極高的靈敏度。 本文對(duì)GPS信號(hào)跟蹤算法進(jìn)行了詳細(xì)的分析研究，針對(duì)兩種不同的應(yīng)用環(huán)境分別提出了改進(jìn)的模型與算法，，并實(shí)驗(yàn)驗(yàn)證了算法的可行性，為今后更復(fù)雜情況下GPS信號(hào)應(yīng)用的研究打下了堅(jiān)實(shí)的基礎(chǔ)。
[Abstract]:GPS (Global Positioning system) is the most perfect satellite navigation and positioning system in the world at present. It can provide continuous and real-time 3D coordinate information, velocity information and time service for most parts of the earth's surface. In recent years, the navigation equipment based on GPS is more and more widely used. In the future, GPS signal tracking is based on the completion of signal acquisition, tracking code phase changes and carrier Doppler changes in real time. It is one of the most important parts of GPS signal processing to realize the accurate synchronization of local replica signal and input signal. The traditional GPS signal tracking loop uses delay Locked loop (DLL) and phase locked loop (PLL) to realize code phase tracking and carrier tracking. However, under the condition of high dynamic or weak signal, the traditional tracking loop is due to its inherent defects. The performance is greatly reduced. Firstly, in the high dynamic environment, because of the large Doppler frequency shift of GPS signal, the traditional tracking loop is easy to lose lock, and the tracking accuracy is not ideal. In this paper, a two-dimensional observation correlator group with Doppler frequency shift and code phase error is adopted, and an iterative extended Kalman filter algorithm based on Levenberg-Marquardt method is proposed. The tracking loop can converge quickly and accurately when the initial acquisition error between the code phase and the carrier frequency is large, and the navigation information can be demodulated successfully. The simulation results show that using the new GPS signal tracking model, the high dynamic GPS signal with an acceleration of 150g can be tracked with high quality. Secondly, a new tracking algorithm is proposed to overcome the difficulty and divergence of the traditional tracking algorithm for weak GPS signals. Adaptive Kalman filter is used to reduce the influence of noise on the signal, and the stability and convergence speed of adaptive Kalman filter algorithm are further improved by Levenberg-Marquardt optimization method. Simulation results show that the new algorithm has good tracking accuracy and high sensitivity for weak GPS signals with low carrier to noise ratio as low as 21dB-Hz. In this paper, the GPS signal tracking algorithm is analyzed and studied in detail. The improved model and algorithm are proposed for two different application environments, and the feasibility of the algorithm is verified by experiments. It will lay a solid foundation for the research of GPS signal application in more complex cases in the future.
【學(xué)位授予單位】：上海交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2013
【分類號(hào)】：P228.4

【二級(jí)參考文獻(xiàn)】

相關(guān)期刊論文 前2條

1 張東和,蕭佐;GPS信號(hào)的多普勒效應(yīng)分析[J];電波科學(xué)學(xué)報(bào);2002年01期

2 沈超;裘正定;;基于MatLab/Simulink的GPS系統(tǒng)仿真[J];系統(tǒng)仿真學(xué)報(bào);2006年07期

本文編號(hào)：1805072