基于海杂波的雷达信号传输特性研究
发布时间：2018-08-28 11:04
【摘要】：处于海洋工作环境下的雷达系统会受到海杂波和多径效应的影响,如何合理有效的从复杂的回波信号中将源信号提取出来,成为现代科学和军事领域一个重要的课题。海杂波作为一种普遍存在的干扰源,对雷达的信号处理、目标检测等会产生很大的影响。建立一个准确的海杂波统计分布模型,不仅能为雷达系统的检测提供了理论依据,而且能抑制杂波,对提高雷达的传输性能起到巨大的作用。当接收到目标的回波信号时,由于海面的散射和反射作用,会产生多径效应,出现时延现象,导致信号的衰弱。本文针对线性调频信号(LFM),建立了多径散射模型,并进行了仿真验证。在此基础上提出了两种基于LFM的多径分离算法,分别为基于高阶累积量和基于分数阶傅里叶变换(FRFT)的方法,并进行了对比分析。结果表明,基于高阶累积量的分离算法相对比较简单,易于实现,在信号的实时处理领域会有很好的效果,但是由于其采样数量大,收敛速度慢,导致稳态误差较大,效果不稳定。而基于FRFT的算法相对而言能更有效地抑制雷达回波信号中的多径分量对LFM信号接收的影响,从而达到更好的分离效果。
[Abstract]:Radar system in marine environment will be affected by sea clutter and multipath effect. How to extract the source signal from complex echo signal reasonably and effectively has become an important subject in modern science and military field. As a common jamming source, sea clutter has great influence on radar signal processing and target detection. Establishing an accurate statistical distribution model of sea clutter can not only provide a theoretical basis for radar system detection, but also suppress clutter, and play a great role in improving the transmission performance of radar. When the echo signal of the target is received, due to the scattering and reflection of the sea surface, the multipath effect will be produced, and the phenomenon of delay will occur, which will lead to the signal weakening. In this paper, a multipath scattering model for linear frequency modulated signal (LFM),) is established and verified by simulation. On this basis, two multipath separation algorithms based on LFM, which are based on higher order cumulants and fractional Fourier transform (FRFT), are proposed and compared. The results show that the separation algorithm based on high-order cumulants is relatively simple and easy to implement, and it will have good results in the field of real-time signal processing. However, due to the large number of samples and the slow convergence rate, the steady-state error is large. The effect is unstable. The algorithm based on FRFT can suppress the influence of multipath component of radar echo signal on the receiving of LFM signal more effectively and achieve better separation effect.
【学位授予单位】：长春理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN957.51
[Abstract]:Radar system in marine environment will be affected by sea clutter and multipath effect. How to extract the source signal from complex echo signal reasonably and effectively has become an important subject in modern science and military field. As a common jamming source, sea clutter has great influence on radar signal processing and target detection. Establishing an accurate statistical distribution model of sea clutter can not only provide a theoretical basis for radar system detection, but also suppress clutter, and play a great role in improving the transmission performance of radar. When the echo signal of the target is received, due to the scattering and reflection of the sea surface, the multipath effect will be produced, and the phenomenon of delay will occur, which will lead to the signal weakening. In this paper, a multipath scattering model for linear frequency modulated signal (LFM),) is established and verified by simulation. On this basis, two multipath separation algorithms based on LFM, which are based on higher order cumulants and fractional Fourier transform (FRFT), are proposed and compared. The results show that the separation algorithm based on high-order cumulants is relatively simple and easy to implement, and it will have good results in the field of real-time signal processing. However, due to the large number of samples and the slow convergence rate, the steady-state error is large. The effect is unstable. The algorithm based on FRFT can suppress the influence of multipath component of radar echo signal on the receiving of LFM signal more effectively and achieve better separation effect.
【学位授予单位】：长春理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN957.51
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