线性调频连续波雷达海杂波建模与回波模拟

发布时间：2018-10-14 15:57

【摘要】：目前对雷达海杂波特性的研究,仍然是以脉冲雷达回波的归一化横截面积的统计模型为主。雷达的海杂波是满足某种概率密度函数的相关序列,这体现在它的幅度分布特性和功率谱特性上。而对线性调频连续波雷达海杂波的研究很少,相关的文献和实测数据也不多。本文根据线性调频连续波雷达的信号处理理论和脉冲雷达的海杂波经典统计模型之间的关系,推导出了线性调频连续波雷达海杂波的计算公式。并且仿真出了在典型的海清下,线性调频连续波雷达海杂波的模型,分析了它的幅度概率密度函数分布特性和功率谱特性。也仿真出了包含海杂波、噪声和点目标的回波模型,应用线性调频连续波雷达“差拍-FFT”的信号处理体制,成功提取预设目标包含距离和速度的信息。本文主要工作概况如下:1.分别分析了锯齿形和对称三角形线性调频连续波雷达在单扫频周期和多扫频周期情况下的动目标回波,根据“差拍-FFT”信号处理体制,介绍了混频后的差拍信号及其傅里叶变换后的特性。分析了脉冲雷达海杂波经典统计模型,应用被广泛认可的杂波建模方法仿真出了几种典型的海杂波模型,仿真出的海杂波与理论值具有很好的吻合性。2.根据线性调频连续波雷达与常规脉冲雷达的特性,建立出了每个扫频周期发射信号与每个发射脉冲之间的关系。根据线性调频连续波雷达的距离分辨率,将雷达照射的区域按径向距离划分成若干个距离单元。从而推导出了线性调频连续波雷达海杂波的计算公式。3.根据推导出的线性调频连续波雷达海杂波的计算公式,分析出了线性调频连续波雷达海杂波距离上的相关性、幅度分布特性和相关特性,并且用仿真数据验证了分析结果的正确性。同时,也仿真出了锯齿形和对称三角形线性调频连续波雷达包含海杂波、噪声和点目标的回波模型。4.对差拍混频后的海杂波距离上的相关性、幅度分布特性和相关特性进行了分析。
[Abstract]:At present, the statistical model of normalized cross section area of pulse radar echo is still used to study the characteristics of radar sea clutter. The sea clutter of radar is a correlation sequence which satisfies a certain probability density function, which is reflected in its amplitude distribution and power spectrum characteristics. However, there are few researches on LFM continuous wave radar sea clutter, and few related literatures and measured data. Based on the relationship between the signal processing theory of linear frequency modulated continuous wave radar and the classical statistical model of sea clutter of pulse radar, a formula for calculating the sea clutter of linear frequency modulated continuous wave radar is derived in this paper. The model of linear frequency modulated continuous wave radar sea clutter under typical sea clear is simulated and its amplitude probability density function distribution characteristic and power spectrum characteristic are analyzed. The echo model including sea clutter, noise and point target is simulated, and the range and velocity information of the preset target is extracted successfully by using the signal processing system of linear frequency modulated continuous wave radar "beat FFT". The main work of this paper is as follows: 1. In this paper, the echo of the moving target in the case of single sweep period and multiple sweep period of zigzag and symmetrical triangular linear frequency modulated continuous wave radar is analyzed, according to the signal processing system of "differential beat FFT", The beat signal after mixing and its characteristics after Fourier transform are introduced. The classical statistical model of pulsed radar sea clutter is analyzed. Several typical sea clutter models are simulated by using the widely accepted clutter modeling method. The simulated sea clutter is in good agreement with the theoretical value. 2. According to the characteristics of linear frequency modulated continuous wave radar and conventional pulse radar, the relationship between each frequency sweeping period transmitting signal and each transmitting pulse is established. According to the range resolution of linear frequency modulated continuous wave radar, the region illuminated by the radar is divided into several range units according to the radial distance. Thus, the formula for calculating the sea clutter of linear frequency modulated continuous wave radar is derived. 3. Based on the deduced formula for calculating the sea clutter of linear frequency modulated continuous wave radar, the correlation, amplitude distribution and correlation characteristics of the range of sea clutter in linear frequency modulated continuous wave radar are analyzed. The correctness of the analysis results is verified by simulation data. At the same time, the echo models of zigzag and symmetric triangular LFM continuous wave radar including sea clutter, noise and point target are also simulated. 4. The correlation, amplitude distribution and correlation characteristics of the sea clutter after subtraction mixing are analyzed.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN957.51

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