本文選題：MIMO雷達 + 認知雷達�。� 參考：《電子科技大學》2014年博士論文

【摘要】：波形設(shè)計是MIMO雷達研究領(lǐng)域的一個關(guān)鍵問題,波形設(shè)計的好壞直接影響其性能。根據(jù)MIMO雷達所承擔任務的不同,通過設(shè)計有針對性的MIMO波形能夠提高雷達性能。因此,研究MIMO雷達波形設(shè)計相關(guān)的理論與算法具有重要意義及應用價值。同時,作為雷達研究領(lǐng)域的新熱點,認知雷達因其特有的“接收到發(fā)射”的閉環(huán)結(jié)構(gòu),使得認知雷達具有更大的提高雷達性能的潛力。而波形設(shè)計是凸顯雷達系統(tǒng)“認知”特性的一個必不可少的環(huán)節(jié),當前,怎樣設(shè)計波形提高認知雷達抑制干擾的能力也受到越來越多的學者的關(guān)注。針對MIMO雷達正交相位編碼信號設(shè)計問題,遺傳算法和模擬退火算法是提高自相關(guān)和互相關(guān)性能常用的優(yōu)化設(shè)計方法,但是不同的應用背景對波形設(shè)計提出了針對性的要求。本文在保證低自相關(guān)旁瓣峰值和低互相關(guān)峰值的基礎(chǔ)上,圍繞波形還必須滿足嚴格正交性以及具有零相關(guān)區(qū)域兩種具體情況開展研究。目前,認知雷達波形的研究成果主要集中在任意波形,由于這些任意波形的包絡(luò)不是恒定的,因此無法充分利用雷達發(fā)射機的效率。針對這一問題,本文以提高雷達性能(如目標檢測概率)為設(shè)計目標,對認知雷達恒包絡(luò)波形設(shè)計開展研究。本文主要針對MIMO雷達正交相位編碼設(shè)計和認知雷達恒包絡(luò)波形設(shè)計的一些關(guān)鍵技術(shù)問題進行研究,取得了一些有益的結(jié)論和成果。本文主要研究工作和創(chuàng)新點如下:1.提出了一種基于Hadamard矩陣的正交二相碼優(yōu)化設(shè)計方法。利用Hadamard矩陣的正交特性,設(shè)計的相位編碼信號不但具有較低的自相關(guān)旁瓣峰值和互相關(guān)峰值,并且兩兩信號間還具有嚴格正交性,有利于改善雷達的目標測量精度和雜波對消效果。該方法僅需要較小的計算機存儲空間就能夠優(yōu)化出較長的相位編碼。因此,可以用于雷達超長相位編碼序列的設(shè)計中。2.研究了基于序列二次規(guī)劃(SQP)算法的類零相關(guān)正交相位編碼優(yōu)化設(shè)計方法。針對MIMO雷達目標檢測性能是由收發(fā)波束形成后輸出的綜合脈壓旁瓣水平直接決定這一問題,將發(fā)射信號的和(簡稱“和信號”)的模糊函數(shù)旁瓣特性引入目標函數(shù)中,利用該方法設(shè)計得到的相位編碼在零相關(guān)區(qū)域不但具有超低的自相關(guān)旁瓣峰值和互相關(guān)峰值,并且和信號的模糊函數(shù)還具有高主副比和優(yōu)良的多普勒容忍性。3.研究了波形旁瓣影響下的機載MIMO雷達雜波特性。對波形旁瓣影響下的機載MIMO雷達雜波回波進行建模,并且理論分析和公式推導了正交波形的自相關(guān)旁瓣和互相關(guān)對機載MIMO雷達雜波秩的影響。在機載MIMO雷達的應用背景下,得到了發(fā)射波形的自相關(guān)旁瓣和互相關(guān)會使得雜波秩明顯增大的結(jié)論。4.針對認知雷達波形設(shè)計問題,分別以最大化信號匹配濾波器輸出端信噪比(SNR)和信雜噪比(SCNR)為設(shè)計準則,研究了色噪聲下和雜波下的恒包絡(luò)波形設(shè)計方法。該方法以待優(yōu)化信號的能量譜密度(ESD)在最小均方誤差意義下逼近最優(yōu)的ESD為目標函數(shù),采用SQP算法進行相位編碼信號的優(yōu)化設(shè)計。與傳統(tǒng)發(fā)射信號如線性調(diào)頻信號(LFM)相比,利用該方法設(shè)計得到的相位編碼信號能夠有效提高輸出的SNR或SCNR。特別地,針對色噪聲下的波形設(shè)計問題,還研究了一種恒包絡(luò)MIMO波形設(shè)計方法。該方法利用了MIMO雷達具有多發(fā)射自由度的特性,進一步提高了輸出的SNR。5.提出了陣元位置誤差影響下的認知發(fā)射方向圖設(shè)計方法。當陣列流形存在誤差時,利用該方法設(shè)計的方向圖在目標方位具有最大發(fā)射增益,同時在一個或多個干擾方向上置零,達到抑制干擾的效果。在此基礎(chǔ)上,還研究了認知空時發(fā)射方向圖設(shè)計方法。與傳統(tǒng)發(fā)射方向圖相比,認知空時發(fā)射方向圖能顯著提高輸出的SCNR,并且能有效減小回波中雜波能量,降低對接收機動態(tài)范圍的要求以及簡化接收端的信號處理結(jié)構(gòu)。
[Abstract]:Waveform design is a key problem in the research field of MIMO radar. The quality of the waveform design directly affects its performance. According to the different tasks of the MIMO radar, the design of the targeted MIMO waveform can improve the performance of the radar. Therefore, it is of great significance and application value to study the theory and algorithm related to the design of the waveform of the MIMO radar. At the same time, as a new hot spot in the field of radar research, cognitive radar has a great potential to improve radar performance because of its unique "receive and transmit" closed loop structure, and the waveform design is an essential link to highlight the cognitive characteristics of radar system. At present, how to design the waveform to improve the cognitive radar The ability to suppress interference is also concerned by more and more scholars. Aiming at the problem of MIMO radar orthogonal phase coded signal design, genetic algorithm and simulated annealing algorithm are the optimal design methods to improve the performance of autocorrelation and cross correlation. However, different application backgrounds have put forward specific requirements for the waveform setting. On the basis of the peak value of the correlation sidelobe and the low cross correlation peak, the waveforms must be studied with strict orthogonality and two specific conditions with zero correlation area. At present, the research results of the cognitive radar waveform are mainly concentrated in arbitrary waveform, because the envelopes of these arbitrary waveforms are not constant, so it is impossible to make full use of the thunder. In order to improve the efficiency of the transmitter, this paper studies the design of the constant envelope waveform design of cognitive radar in order to improve the performance of radar (such as target detection probability). This paper mainly studies some key technical problems in the design of MIMO radar orthogonal phase coding and the design of the constant envelope waveform of cognitive radar. Useful conclusions and achievements. The main research work and innovation in this paper are as follows: 1. an orthogonal binary phase code optimization design method based on Hadamard matrix is proposed. Using the orthogonal characteristics of the Hadamard matrix, the designed phase coded signal not only has lower autocorrelation side lobe peak value and cross correlation peak value, but also is strict between the 22 signals. Lattice orthogonality is helpful to improve the precision of radar target measurement and the effect of clutter cancellation. This method can optimize the long phase encoding only with small computer storage space. Therefore,.2. can be used in the design of the radar super long phase coding sequence, which is based on the zero correlation orthogonal phase based on the sequence two programming (SQP) algorithm. The optimization design method of bit coding is designed to directly determine the problem that the target detection performance of MIMO radar is the integrated pulse side lobe level of the output of the receiving beam after the beam formation. The fuzzy function sidelobe characteristic of the transmitted signal and ("and the signal") is introduced into the target function, and the phase code obtained by this method is used in the zero correlation area. The domain not only has ultra low autocorrelation sidelobe peaks and cross correlation peaks, but also has high principal to side ratio and excellent Doppler tolerance.3. to study the clutter characteristics of airborne MIMO radar under the influence of waveform sidelobe. Modeling of airborne MIMO radar clutter echo under the influence of waveform sidelobe and theoretical analysis The formula derives the influence of autocorrelation sidelobe and cross correlation on the clutter rank of airborne MIMO radar. In the application background of airborne MIMO radar, the autocorrelation sidelobe and cross correlation of the transmitted waveform can make the clutter rank increase obviously..4. is used to maximize the signal matching filter for the recognition of the cognitive radar waveform. The output terminal signal to noise ratio (SNR) and signal to clutter ratio (SCNR) are designed. The design method of constant envelope waveform under the color noise and the clutter is studied. The method is designed to optimize the ESD as the optimal approximation of the energy spectral density (ESD) of the optimized signal in the sense of the minimum mean square error. The SQP algorithm is used to optimize the phase coded signal. Compared with the traditional transmission signal such as linear frequency modulation signal (LFM), the phase coded signal designed by this method can effectively improve the output SNR or SCNR.. In view of the design of the waveform under the color noise, a design method of the constant envelope MIMO waveform is also studied. This method takes advantage of the characteristics of the MIMO radar with multiple emission degrees of freedom. The design method of cognitive emission pattern design under the influence of array element position error is proposed. When there is error in the array manifold, the pattern designed by this method has the maximum emission gain at the target orientation and zero in one or more interference directions, and the effect of interference suppression is achieved on the basis of this method. The cognitive space-time emission pattern design method is also studied. Compared with the traditional emission pattern, the cognitive space-time emission pattern can significantly improve the output SCNR, and can effectively reduce the clutter energy in the echo, reduce the dynamic range of the receiver and simplify the signal processing structure of the receiver.
【學位授予單位】：電子科技大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：TN958
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本文編號：2062525