本文選題：衛(wèi)星編隊(duì) + 分布式MIMO　； 參考：《電子科技大學(xué)》2014年碩士論文

【摘要】：衛(wèi)星通信作為當(dāng)下通信的主要方式之一,在軍事應(yīng)用和航天科技領(lǐng)域具有重要的地位。隨著衛(wèi)星通信事業(yè)的發(fā)展,各個(gè)國(guó)家紛紛發(fā)射了許多衛(wèi)星,導(dǎo)致軌道資源和頻譜資源越來越珍貴。為了滿足日益發(fā)展的衛(wèi)星通信需求,節(jié)省研制和發(fā)射成本,微小衛(wèi)星的研制逐漸進(jìn)入了人們的視野。對(duì)微小衛(wèi)星進(jìn)行編隊(duì)除了能使其具有單顆大衛(wèi)星的功能之外,還具有覆蓋更靈活、系統(tǒng)更穩(wěn)健、更新周期更短、成本更低廉的優(yōu)點(diǎn)�，F(xiàn)有的微小衛(wèi)星編隊(duì)方法計(jì)算復(fù)雜度高,誤差會(huì)隨著時(shí)間變大,不適合實(shí)際應(yīng)用。為了方便初期理論分析,本文第二章根據(jù)衛(wèi)星編隊(duì)飛行時(shí)相對(duì)運(yùn)動(dòng)的軌道參數(shù)提出了一種新的編隊(duì)構(gòu)型設(shè)計(jì)方法,能夠根據(jù)期望的隊(duì)形簡(jiǎn)便地計(jì)算出繞飛衛(wèi)星的軌道根數(shù)。對(duì)衛(wèi)星進(jìn)行編隊(duì)是構(gòu)成分布式衛(wèi)星MIMO系統(tǒng)的基礎(chǔ)。衛(wèi)星分布式MIMO系統(tǒng)可以利用編隊(duì)的分布式構(gòu)型,為通信信道提供空間宏分集,增大信道容量。本文第三章對(duì)MIMO系統(tǒng)的空域相關(guān)性和容量進(jìn)行了分析,得出了影響MIMO系統(tǒng)空間相關(guān)性的因素以及MIMO信道相關(guān)性對(duì)其信道容量的影響。在此基礎(chǔ)上研究了極化天線去相關(guān)技術(shù)對(duì)MIMO系統(tǒng)相關(guān)性、容量和誤碼率的改善。最后提出了一種搭載極化天線的衛(wèi)星分布式MIMO系統(tǒng)的模型,并以此模型為基礎(chǔ),對(duì)編隊(duì)衛(wèi)星分布式MIMO系統(tǒng)的信道容量和誤碼率進(jìn)行了進(jìn)一步仿真分析。證明利用極化分集的編隊(duì)衛(wèi)星分布式MIMO比傳統(tǒng)的單天線系統(tǒng)和集中式MIMO系統(tǒng)有更大的信道容量和更好的誤碼率性能。智能天線技術(shù)和分布式MIMO系統(tǒng)相結(jié)合,可以進(jìn)一步增加編隊(duì)衛(wèi)星分布式MIMO系統(tǒng)的容量和抗干擾性能。智能天線波束成形技術(shù)可以有效控制衛(wèi)星點(diǎn)波束的指向,從空域上實(shí)現(xiàn)干擾消除和信號(hào)增強(qiáng)。實(shí)現(xiàn)波束成形有LMS算法、RLS算法等。本文第四章先對(duì)LMS算法和RLS算法進(jìn)行了仿真,然后對(duì)LMS波束成形算法進(jìn)行了改進(jìn),給出了一種簡(jiǎn)化的變步長(zhǎng)LMS算法。該算法對(duì)迭代誤差范圍進(jìn)行判斷,在某個(gè)范圍內(nèi)使用一種步長(zhǎng)。使得求解天線元權(quán)值向量的迭代過程中不需要頻繁地對(duì)步長(zhǎng)進(jìn)行求解,從而達(dá)到減少算法復(fù)雜度,節(jié)約硬件資源的目的,符合小衛(wèi)星硬件資源少、功耗低的特點(diǎn)。經(jīng)過仿真驗(yàn)證,該算法是有效的。本文第五章是結(jié)束語,對(duì)全文的工作成果以及不足的地方進(jìn)行了總結(jié),并計(jì)劃了下一步的工作。
[Abstract]:As one of the main communication methods, satellite communication plays an important role in military applications and space science and technology. With the development of satellite communications, many countries have launched many satellites, resulting in more and more precious orbital and spectrum resources. In order to meet the increasing demand of satellite communication and save the cost of research and launch, the development of micro satellite has gradually entered the field of vision. The formation of small satellites not only makes them have the function of single large satellite, but also has the advantages of more flexible coverage, more robust system, shorter update period and lower cost. The existing small satellite formation methods have high computational complexity and the error will increase with time, so it is not suitable for practical application. In order to facilitate the initial theoretical analysis, a new formation configuration design method is proposed according to the orbit parameters of the relative motion of satellite formation flying in the second chapter, which can easily calculate the orbital root number of flying satellites according to the expected formation. Satellite formation is the foundation of distributed satellite MIMO system. Satellite distributed MIMO system can use the distributed configuration of formation to provide spatial macro diversity for communication channel and increase channel capacity. In the third chapter, the spatial correlation and capacity of MIMO system are analyzed, and the factors affecting spatial correlation of MIMO system and the influence of MIMO channel correlation on channel capacity are obtained. On this basis, the improvement of correlation, capacity and bit error rate of MIMO system by polarization antenna de-correlation technique is studied. Finally, a model of satellite distributed MIMO system with polarized antenna is proposed. Based on the model, the channel capacity and bit error rate (BER) of distributed MIMO system are simulated and analyzed. It is proved that the distributed MIMO with polarization diversity has greater channel capacity and better bit error rate performance than the traditional single-antenna system and centralized MIMO system. The combination of smart antenna technology and distributed MIMO system can further increase the capacity and anti-jamming performance of formation satellite distributed MIMO system. Smart antenna beamforming technology can effectively control the satellite spot beam pointing, from the airspace interference cancellation and signal enhancement. The realization of beamforming includes LMS algorithm, RLS algorithm and so on. In the fourth chapter, the LMS algorithm and the RLS algorithm are simulated, then the LMS beamforming algorithm is improved, and a simplified variable step size LMS algorithm is presented. The algorithm determines the range of iterative error and uses a step size in a certain range. In order to reduce the complexity of the algorithm and save the hardware resources, it is not necessary to solve the step size frequently in the iterative process of solving the antenna element weight vector, which is in line with the characteristics of small satellite hardware resources and low power consumption. Simulation results show that the algorithm is effective. The fifth chapter is the conclusion, summarizes the work achievements and shortcomings of the paper, and plans the next work.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN927.2

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本文編號(hào)：1792540