【摘要】：極化敏感陣列(PSA)可以獲取入射電磁波的極化狀態(tài),相比于標(biāo)量陣列其具有諸多性能優(yōu)勢(shì),成為近些年來(lái)的熱點(diǎn)研究課題之一。然而目前針對(duì)極化陣列的處理方法,大多是傳統(tǒng)陣列處理方法的直接拓展,沒(méi)有過(guò)多利用極化陣列的特殊流型結(jié)構(gòu),極化陣列處理的性能還有待進(jìn)一步提高。針對(duì)這一問(wèn)題,本文主要針對(duì)極化陣列參數(shù)估計(jì)和波束形成的方法展開(kāi)研究,充分利用電偶極子對(duì)的正交結(jié)構(gòu),且基于一種分布式極化陣列布陣模型給出了參數(shù)估計(jì)和波束形成的方法,并通過(guò)計(jì)算機(jī)仿真給出了實(shí)驗(yàn)結(jié)果。針對(duì)極化陣列參數(shù)估計(jì),同時(shí)考慮入射非相干和相干信源的情況。針對(duì)非相干信源,給出了常見(jiàn)的Lv-Music和極化ESPRIT參數(shù)估計(jì)算法,并利用兩分量陣列的流型結(jié)構(gòu),基于四元數(shù)Music方法完成了參數(shù)估計(jì)。計(jì)算機(jī)仿真結(jié)果表明基于四元數(shù)的方法多參數(shù)估計(jì)性能優(yōu)于基于復(fù)數(shù)的方法。針對(duì)相干信源,給出了極化陣列空間平滑和極化平滑解相干算法,并給出了二者的改進(jìn)方法。仿真結(jié)果表明文中改進(jìn)算法具有更低的參數(shù)估計(jì)均方根誤差和更好的角度分辨力,且改進(jìn)的極化平滑算法還具有對(duì)噪聲的適應(yīng)性。針對(duì)極化陣列波束形成,介紹了聯(lián)合濾波的原理和準(zhǔn)則,給出了常規(guī)的波束形成和基于四元數(shù)的波束形成方法。基于特征空間的思想,推導(dǎo)了導(dǎo)數(shù)約束和零點(diǎn)約束條件下的最優(yōu)加權(quán)矢量,并通過(guò)仿真驗(yàn)證不同約束條件對(duì)聯(lián)合濾波波束方向圖和濾波性能的影響。利用兩分量極化陣列共點(diǎn)分量之間固有的正交特性,推導(dǎo)了基于四元數(shù)的波束形成,包括Q-MVDR和Q-APES算法,給出了算法的理論推導(dǎo)得到了最優(yōu)加權(quán)矢量的表達(dá)式。計(jì)算機(jī)仿真結(jié)果表明,Q-APES算法在目標(biāo)信號(hào)功率較大、快拍數(shù)較少、干擾與目標(biāo)信號(hào)相干的情況下都具有穩(wěn)定的波束圖,且在極化陣列存在指向誤差時(shí)也表現(xiàn)具有一定的穩(wěn)健性。為了有效減少極化陣列共點(diǎn)分量之間互耦的影響,降低硬件實(shí)現(xiàn)的成本和算法處理的復(fù)雜度,考慮將兩分量極化陣列陣元各分量在空間交替分散放置。給出了一種分布式極化陣列的布陣模型,利用其流型結(jié)構(gòu)特點(diǎn)完成了參數(shù)估計(jì)和波束形成方法的理論推導(dǎo),并與兩分量共點(diǎn)極化陣列和傳統(tǒng)的標(biāo)量陣列分別在不同條件下對(duì)比了參數(shù)估計(jì)和聯(lián)合濾波的性能。
[Abstract]:Polarization-sensitive array (PSA) can obtain the polarization state of incident electromagnetic wave. Compared with scalar array, it has many performance advantages and has become one of the hot research topics in recent years. However, most of the current processing methods for polarization array are the direct expansion of traditional array processing methods, and the performance of polarization array processing needs to be further improved without making too much use of the special flow pattern structure of polarization array. In order to solve this problem, this paper mainly studies the parameter estimation of polarization array and the beamforming method, and makes full use of the orthogonal structure of electric dipole pair. The method of parameter estimation and beamforming based on a distributed polarization array model is given, and the experimental results are given by computer simulation. For the parameter estimation of polarization array, the incident incoherent and coherent sources are considered at the same time. For incoherent sources, common Lv-Music and polarimetric ESPRIT parameter estimation algorithms are presented, and the parameters are estimated based on quaternion Music method using the flow pattern structure of two-component array. The results of computer simulation show that the performance of multi-parameter estimation based on quaternion is better than that based on complex number. For coherent sources, the spatial smoothing and polarimetric smoothing algorithms of polarimetric array are presented, and the improved methods are given. The simulation results show that the improved algorithm has lower root mean square error and better angular resolution, and the improved polarization smoothing algorithm is adaptive to noise. Aiming at polarization array beamforming, the principle and criterion of joint filtering are introduced, and the conventional beamforming and quaternion based beamforming methods are presented. Based on the idea of feature space, the optimal weighted vector with derivative constraint and zero constraint is derived, and the effects of different constraints on the beam pattern and filtering performance of joint filtering are verified by simulation. Based on the inherent orthogonality between the common point components of a two-component polarization array, a quaternion based beamforming algorithm, including Q-MVDR and Q-APES algorithms, is derived. The theoretical derivation of the algorithm is given to obtain the expression of the optimal weighted vector. The computer simulation results show that the Q-APES algorithm has a stable beam diagram when the signal power of the target is large, the number of rapids is small, and the interference is coherent with the target signal. And the polarization array has some robustness when there is pointing error. In order to reduce the influence of mutual coupling between common point components of polarization array, reduce the cost of hardware implementation and the complexity of algorithm processing, we consider placing the components of two-component polarization array alternately in space. An array model of distributed polarization array is presented. The theoretical derivation of parameter estimation and beamforming method is completed by using its flow pattern structure. The performance of parameter estimation and joint filtering are compared with two-component co-point polarization array and traditional scalar array under different conditions.
【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】：2015
【分類(lèi)號(hào)】：TN911.7

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相關(guān)期刊論文 前1條

1 李會(huì)勇;劉芳;王宇;樊勇;何子述;;極化域-空域聯(lián)合的四元數(shù)APES波束形成算法[J];信號(hào)處理;2014年10期

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本文編號(hào)：2385458