机载认知MIMO雷达空时优化设计研究

发布时间：2018-10-12 12:21

【摘要】：认知雷达不仅具有接收自适应能力,而且通过接收端到发射端的反馈可以获得发射端的自适应能力,因此,认知雷达是一个闭环的自适应系统。MIMO雷达具有比相控阵雷达更高的发射自由度,将MIMO雷达与认知雷达结合的认知MIMO雷达是广受学者关注的新体制雷达。本文将认知MIMO雷达运用到机载平台,结合理论推导和建模仿真,研究了机载平台下色噪声及杂波的抑制问题,主要工作内容如下:1、介绍了机载认知MIMO雷达的基本系统框架以及可行布阵方式,说明了认知信息获取及空时优化设计的基本方法,详细介绍了机载平台下的杂波建模和信息提取方法。2、研究了机载认知MIMO雷达的波形设计问题,以最大化SNR为准则,分析了多种基于特征值的波形设计方法,并重点研究了色噪声情况下的恒模波形设计方法,该方法以基于特征值方法优化的波形为目标波形,采用序贯二次规划进行MIMO波形编码,该方法充分利用了发射阵元的自由度及发射功率,进一步提高了输出SNR。3、研究了机载认知MIMO雷达的发射空时权设计问题。分别对相控阵模式及MIMO模式下的发射空时权优化方法进行了介绍和仿真,相控阵模式下的空时权优化采用MVDR方法,可以在发射空时方向图上形成对应杂波脊的凹槽;MIMO模式下的空时权优化通过引入转移矩阵,以最大化SCNR为准则,进行问题建模和优化求解,可以有效抑制杂波,同时可以降低对接收机动态范围的要求,简化接收端信号处理的结构。4、针对复杂电磁环境,研究了机载认知MIMO雷达的空时频三维优化问题。针对杂波和平稳色噪声背景,采用分步优化,即时域波形优化抑制色噪声的影响,空频域优化抑制杂波;针对杂波和非平稳色噪声环境,采用空时频三维联合优化,同时抑制杂波、干扰和色噪声的影响。
[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.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：V243.2

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