【摘要】：認(rèn)知雷達(dá)不僅具有接收自適應(yīng)能力,而且通過(guò)接收端到發(fā)射端的反饋可以獲得發(fā)射端的自適應(yīng)能力,因此,認(rèn)知雷達(dá)是一個(gè)閉環(huán)的自適應(yīng)系統(tǒng)。MIMO雷達(dá)具有比相控陣?yán)走_(dá)更高的發(fā)射自由度,將MIMO雷達(dá)與認(rèn)知雷達(dá)結(jié)合的認(rèn)知MIMO雷達(dá)是廣受學(xué)者關(guān)注的新體制雷達(dá)。本文將認(rèn)知MIMO雷達(dá)運(yùn)用到機(jī)載平臺(tái),結(jié)合理論推導(dǎo)和建模仿真,研究了機(jī)載平臺(tái)下色噪聲及雜波的抑制問(wèn)題,主要工作內(nèi)容如下:1、介紹了機(jī)載認(rèn)知MIMO雷達(dá)的基本系統(tǒng)框架以及可行布陣方式,說(shuō)明了認(rèn)知信息獲取及空時(shí)優(yōu)化設(shè)計(jì)的基本方法,詳細(xì)介紹了機(jī)載平臺(tái)下的雜波建模和信息提取方法。2、研究了機(jī)載認(rèn)知MIMO雷達(dá)的波形設(shè)計(jì)問(wèn)題,以最大化SNR為準(zhǔn)則,分析了多種基于特征值的波形設(shè)計(jì)方法,并重點(diǎn)研究了色噪聲情況下的恒模波形設(shè)計(jì)方法,該方法以基于特征值方法優(yōu)化的波形為目標(biāo)波形,采用序貫二次規(guī)劃進(jìn)行MIMO波形編碼,該方法充分利用了發(fā)射陣元的自由度及發(fā)射功率,進(jìn)一步提高了輸出SNR。3、研究了機(jī)載認(rèn)知MIMO雷達(dá)的發(fā)射空時(shí)權(quán)設(shè)計(jì)問(wèn)題。分別對(duì)相控陣模式及MIMO模式下的發(fā)射空時(shí)權(quán)優(yōu)化方法進(jìn)行了介紹和仿真,相控陣模式下的空時(shí)權(quán)優(yōu)化采用MVDR方法,可以在發(fā)射空時(shí)方向圖上形成對(duì)應(yīng)雜波脊的凹槽;MIMO模式下的空時(shí)權(quán)優(yōu)化通過(guò)引入轉(zhuǎn)移矩陣,以最大化SCNR為準(zhǔn)則,進(jìn)行問(wèn)題建模和優(yōu)化求解,可以有效抑制雜波,同時(shí)可以降低對(duì)接收機(jī)動(dòng)態(tài)范圍的要求,簡(jiǎn)化接收端信號(hào)處理的結(jié)構(gòu)。4、針對(duì)復(fù)雜電磁環(huán)境,研究了機(jī)載認(rèn)知MIMO雷達(dá)的空時(shí)頻三維優(yōu)化問(wèn)題。針對(duì)雜波和平穩(wěn)色噪聲背景,采用分步優(yōu)化,即時(shí)域波形優(yōu)化抑制色噪聲的影響,空頻域優(yōu)化抑制雜波;針對(duì)雜波和非平穩(wěn)色噪聲環(huán)境,采用空時(shí)頻三維聯(lián)合優(yōu)化,同時(shí)抑制雜波、干擾和色噪聲的影響。
[Abstract]:Cognitive radar not only has adaptive ability to receive, but also can obtain adaptive capability of transmitter through feedback from receiver to transmitter. Cognitive radar is a closed-loop adaptive system. MIMO radar has higher degree of freedom than phased array radar. The cognitive MIMO radar which combines MIMO radar and cognitive radar is a new system radar which is widely concerned by scholars. In this paper, the cognitive MIMO radar is applied to the airborne platform. Combining with theoretical derivation and modeling and simulation, the suppression of color noise and clutter under the airborne platform is studied. The main work is as follows: 1. The basic system framework and feasible array method of airborne cognitive MIMO radar are introduced, and the basic methods of cognitive information acquisition and space-time optimization design are explained. The methods of clutter modeling and information extraction under airborne platform are introduced in detail. 2. The waveform design of airborne cognitive MIMO radar is studied. Taking maximization SNR as the criterion, several waveform design methods based on eigenvalue are analyzed. The design method of constant modulus waveform in the case of color noise is studied. The waveform optimized based on eigenvalue method is taken as the target waveform, and the sequential quadratic programming is used to code the MIMO waveform. This method makes full use of the degree of freedom and the transmitting power of the emitter elements, and further improves the output SNR.3, to study the design of space-time weight of airborne cognitive MIMO radar. The methods of space-time weight optimization in phased array mode and MIMO mode are introduced and simulated respectively. The MVDR method is used to optimize space-time weight in phased array mode. The grooves corresponding to clutter ridges can be formed on the transmitted space-time pattern, and the optimization of space-time weights in MIMO mode can effectively suppress clutter by introducing transfer matrix and using maximization SCNR as the criterion to model and solve the problem. At the same time, it can reduce the requirement of receiver dynamic range and simplify the structure of receiver signal processing. 4. For complex electromagnetic environment, the space-time-frequency optimization problem of airborne cognitive MIMO radar is studied. For clutter and stationary color noise background, step by step optimization and real-time waveform optimization are used to suppress the influence of color noise, space-frequency domain optimization is used to suppress clutter, and for clutter and non-stationary color noise environment, three dimensional space-time-frequency joint optimization is adopted. At the same time, the effects of clutter, interference and color noise are suppressed.
【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】：2016
【分類號(hào)】：V243.2

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本文編號(hào)：2266093