【作者】 高明；

【导师】 张民；

【作者基本信息】 西安电子科技大学 ， 无线电物理， 2017， 硕士

【摘要】 雷达在实际工作的时候往往面临着杂波干扰,这对雷达探测性能形成了严重的制约,因此对于雷达杂波的形成机理和统计特征的研究一直是业界关注的热点。经过国内外众多学者几十年的努力,在杂波理论模型方面已经取得了诸多成果。但是目前大多数的成果都是基于理论仿真,而将理论研究成果与实际工程产品相结合的研究则相对较少。结合杂波理论模型,用硬件实现出各种杂波,最终研制出雷达杂波模拟器,用于解决雷达外场测试的各种问题,缩短雷达测试周期和测试成本,具有实际应用价值。本文主要工作是基于雷达杂波统计模型,通过数字信号处理器(DSP)搭建的平台,实现几种典型海杂波的模拟仿真。论文主要工作如下:1.通过对比分析,确定本文硬件开发平台为TL6748-EasyEVM开发板,DSP芯片型号为TMS320C6748,软件开发平台为Code Composer Studio。结合软硬件平台,详细说明了开发环境的各项配置工作,为后续杂波模拟工作提供充分的保障。2.在分析三种经典幅度分布模型和三种常用功率谱模型的表达形式以及适用范围之后,结合具体DSP项目的开发流程,使用频域变换和逆累积分布函数方法,在DSP上模拟生成一维常见相关和不相关杂波,与预期值对比,模拟结果符合较好。3.为了使模拟的雷达杂波在各项细节方面更加接近实测数据,本文提出了基于自回归模型的非平稳K分布杂波的仿真方法。结合IPIX雷达实测数据,分析实测数据的幅值分布特征和功率谱特性,发现复合K分布更加适合描述IPIX雷达数据的幅度特征,并且实际杂波具有非平稳特性,即杂波幅度包络和功率谱中心频率随时间变化而变化。在DSP上实现了基于该方法的杂波模拟,模拟结果符合预期,说明该方法能够在DSP上有效模拟具有非平稳特性的K分布杂波。4.在详细讨论海杂波的时间相关性和空间相关性的基础上,提出将时空相关特性整体使用一个相关矩阵表示的方法,并且考虑杂波幅度分布的长拖尾效应,分析了Pareto分布模型的优势。结合DSP上的二维频域变换方法的具体实现,使用硬件平台模拟了时空相关二维Pareto分布杂波,模拟结果与预期结果符合较好,证明了DSP模拟二维时空相关海杂波的可行性。更多还原

【Abstract】 When the radar is working,it is often faced with clutter interference,which seriously restricts the radar detection performance,so the study of radar clutter mechanism and statistical characteristics of the industry has been concerned about the hot spots.After many decades of domestic and foreign scholars efforts,the clutter theory model has made many achievements.However,most of the clutter research results are based on theoretical simulation,the theoretical research combined with the application of hardware research is not much.According to the clutter model,the hardware implementation of a variety of clutter,finally developed radar clutter simulator used to solve various problems in radar field test,shorten the radar test cycle and testing cost,has great practical value.The main work of this paper is based on the statistical model of radar clutter,using digital signal processor platform to realize the simulation of several typical sea clutter.The work of the paper mainly from the following aspects: 1.Through the comparative analysis,to determine the hardware development platform is TL6748-Easy EVM development board,DSP chip is TMS320C6748,software development platform is Code Composer Studio.And then combined with the hardware and software platform,a detailed description of the development environment of the configuration work for the follow-up clutter simulation work to provides a guarantee..2.After analyzing the expression patterns of three classical amplitude distribution models and three common power spectrum models and the application scope,combined with the development process of specific DSP projects,the frequency domain transformation and inverse cumulative distribution function method are used to simulate one-dimensional correlated clutter and uncorrelated clutter on the DSP.Compared with the expected value,the simulation results are in good agreement.3.In order to make the simulated radar clutter more close to the measured data in detail,this paper presents a simulation method of non-stationary K-distributed clutter based on autoregressive(AR)model.Based on the measured data of IPIX radar,the amplitude distribution and power spectrum characteristics of the measured data are analyzed.It is found that the composite K distribution is more suitable for describing the amplitude characteristics of IPIX radar data,and the actual clutter has non-stationary characteristics,that is,the clutter amplitude envelope and The center frequency of the power spectrum varies with time.Finally,the clutter simulation based on this method is realized on the DSP,and the simulation results are in agreement with the expectation.The method can effectively simulate the K-distributed clutter with non-stationary characteristics on the DSP.4.After a careful examination on the temporal correlation and spatial correlation of sea clutter,the paper proposes the method of space-time correlation characteristic of whole using a correlation matrix representation,and considering the long tail clutter amplitude distribution,analyzes the advantages of Pareto distribution model.Combined with the concrete realization of the two-dimensional frequency domain transform method on the DSP,the space-time two-dimensional Pareto distributed clutter is simulated by the hardware platform.The simulation results are in good agreement with the expected results,which proves the feasibility of DSP simulating two-dimensional spatiotemporal correlation clutter.更多还原