本文選題：偽衛(wèi)星 + 直接序列擴頻　； 參考：《西安電子科技大學(xué)》2014年碩士論文

【摘要】：全球衛(wèi)星導(dǎo)航系統(tǒng)的飛速發(fā)展使得衛(wèi)星導(dǎo)航應(yīng)用越來越廣泛。在設(shè)計和開發(fā)衛(wèi)星導(dǎo)航終端過程中,測試接收機對衛(wèi)星信號的捕獲跟蹤能力是十分重要的環(huán)節(jié),而在受遮擋的室內(nèi)區(qū)域可見星數(shù)目很少甚至沒有可見的衛(wèi)星,這給產(chǎn)品的設(shè)計帶來不便。設(shè)計一款室內(nèi)偽衛(wèi)星導(dǎo)航星源模擬器就可以很好的解決上述問題。本文的目的是設(shè)計一款可以模擬衛(wèi)星信號的硬件系統(tǒng),在此平臺上通過編寫軟件來模擬產(chǎn)生用戶位置處的衛(wèi)星信號。論文簡述了課題的研究背景及現(xiàn)狀,闡述了論文的研究意義,分析了偽衛(wèi)星信號的結(jié)構(gòu)、擴頻碼的構(gòu)成、導(dǎo)航電文的規(guī)范,研究了直接序列擴頻技術(shù)。在理論研究與分析的基礎(chǔ)之上,設(shè)計了室內(nèi)偽衛(wèi)星導(dǎo)航星源模擬器。系統(tǒng)的硬件主要由基帶部分和射頻部分組成�；鶐Р糠衷O(shè)計基于FPGA+DSP架構(gòu)硬件平臺,主要完成數(shù)字基帶信號的生成。射頻部分主要完成中頻信號的模擬上變頻。模擬器的軟件部分的設(shè)計采用自頂向下,模塊化設(shè)計的思想,完成了系統(tǒng)接口軟件設(shè)計、DSP部分的衛(wèi)星軌道計算模塊、衛(wèi)星可見性判斷模塊、延遲參數(shù)計算模塊的設(shè)計以及FPGA部分的擴頻碼生成模塊、載波生成模塊、擴頻調(diào)制模塊及各個芯片的驅(qū)動模塊的設(shè)計等。系統(tǒng)工作原理為,DSP根據(jù)初始參數(shù)和算法模型計算并生成導(dǎo)航電文,FPGA接收DSP生成的導(dǎo)航電文,通過直接序列擴頻調(diào)制完成基帶信號的生成,數(shù)模轉(zhuǎn)換模塊對FPGA輸出的中頻信號進行數(shù)字到模擬的轉(zhuǎn)換,射頻部分的上變頻模塊配合本振模塊將中頻模擬信號變頻到GPS的L1載頻上,實現(xiàn)偽衛(wèi)星信號的模擬。在測試與驗證部分,對C/A碼的波形、擴頻調(diào)制的波形進行了實測,分別對導(dǎo)航星源模擬器的中頻信號和射頻信號進行了頻譜分析。借助實驗室的GPS接收平臺對模擬器射頻輸出的信號進行了測試,接收機能夠完成同步并解算出導(dǎo)航數(shù)據(jù)。測試結(jié)果表明,整個室內(nèi)偽衛(wèi)星模擬器系統(tǒng)能夠滿足設(shè)計要求。
[Abstract]:The rapid development of global satellite navigation system makes the application of satellite navigation more and more extensive. In the process of designing and developing satellite navigation terminals, it is very important to test the acquisition and tracking ability of the receiver to satellite signals, and there are few or no visible satellites in the occluded indoor area. This brings inconvenience to the design of the product. Design an indoor pseudosatellite navigation star source simulator can solve the above problems. The purpose of this paper is to design a hardware system which can simulate the satellite signal. On this platform, the software is written to simulate the satellite signal at the user's position. This paper briefly introduces the research background and present situation of the subject, expounds the significance of the research, analyzes the structure of the pseudosatellite signal, the structure of the spread spectrum code, the standard of the navigation message, and studies the direct sequence spread spectrum technology. On the basis of theoretical research and analysis, the indoor pseudosatellite navigation star source simulator is designed. The hardware of the system is mainly composed of baseband part and RF part. The baseband part is based on FPGA DSP architecture hardware platform, mainly completes the digital baseband signal generation. The RF part mainly completes the analog up-conversion of if signal. The software design of the simulator adopts the idea of top-down and modularization design. The system interface software designs the satellite orbit calculation module and the satellite visibility judgment module of DSP part. The design of delay parameter calculation module and FPGA part of the spread spectrum code generation module, carrier generation module, spread spectrum modulation module and each chip driver module design and so on. The working principle of the system is that DSP calculates and generates navigation message based on initial parameters and algorithm model, and FPGA receives the navigation message generated by DSP. The baseband signal is generated by direct sequence spread spectrum modulation. Digital to analog conversion module to FPGA output if signal digital to analog conversion, radio frequency upconversion module with local oscillator module to convert if analog signal to GPS L1 carrier frequency, to achieve pseudosatellite signal simulation. In the part of test and verification, the waveform of C / A code and the waveform of spread spectrum modulation are measured, and the intermediate frequency signal and radio frequency signal of the navigation star source simulator are analyzed respectively. With the help of the GPS receiving platform in the laboratory, the RF output signal of the simulator is tested, and the receiver can complete the synchronization and solve the navigation data. The test results show that the whole indoor pseudosatellite simulator system can meet the design requirements.
【學(xué)位授予單位】：西安電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN967.1

【參考文獻】

相關(guān)碩士學(xué)位論文 前1條

1 羅益鴻;導(dǎo)航衛(wèi)星信號模擬器軟件設(shè)計與實現(xiàn)[D];國防科學(xué)技術(shù)大學(xué);2008年

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本文編號：2118148