基于空时自适应处理的展宽海杂波抑制

发布时间：2018-01-16 15:30

本文关键词：基于空时自适应处理的展宽海杂波抑制　出处：《哈尔滨工业大学》2014年硕士论文　论文类型：学位论文

【摘要】：天发地收高频雷达由于其双基地特征和天波路径电离层扰动的影响，导致其一阶海杂波具有明显的空时耦合性和多普勒谱展宽，会淹没其附近的慢速舰船目标。本文结合混合体制系统工作原理推导了双重因素下的展宽一阶海杂波波束-多普勒空时分布，并率先将空时自适应处理(Space-Time Adaptive Process-STAP)算法应用于混合体制系统展宽一阶海杂波的抑制中。首先分析了混合体制系统的电波传播路径，将双基地特征与电离层非均匀扰动特性相结合对混合体制系统一阶海杂波分布进行仿真分析，理论仿真分析可以较好的反应其实际分布。以仿真模型为基础，在存在电离层扰动的情况下对全局空时处理和基于降维处理的局域联合处理(Joint Domain Localized-JDL)算法进行了仿真分析，结果表明JDL算法可以在明显降低运算量和训练样本需求量的情况下有效的抑制杂波、发现目标。定量分析了不同程度、不同形式的电离层污染对一阶海杂波空时耦合性的影响，及给空时处理带来的信杂比损失。将JDL算法用于抑制实际背景下的非均匀一阶海杂波，提出滤除当前待检测距离维样本的目标信息、并把上述单元视为常规样本数据用于估计杂波协方差矩阵，可以明显提高目标及其附近局域的杂波抑制性能。结合训练样本加权的思想，将距离维的输出作为赋予每个训练样本的权值，并将加权后的训练样本重新代入到协方差矩阵的估计中。将一阶海杂波的理论空时分布作为先验知识用于空时处理算法中，对已知的杂波区不进行目标滤除处理，可以明显增加杂波区的空时凹口深度。经过改进的JDL算法可以在实际背景下的目标检测中收获明显的输入输出信杂比改善。
[Abstract]:Because of its bistatic characteristics and the influence of ionospheric disturbance, the first order sea clutter has obvious space-time coupling and Doppler spectrum broadening. This paper deduces the beam-Doppler space-time distribution of the broadened first order sea clutter under double factors combined with the working principle of the hybrid system. Space-Time Adaptive Process-STAP algorithm is first applied to the suppression of first-order sea clutter in hybrid systems. Firstly, the propagation path of the hybrid system is analyzed, and the first order sea clutter distribution of the hybrid system is simulated by combining the bistatic characteristics with the ionospheric nonuniform disturbance. Theoretical simulation analysis can well reflect its actual distribution. Based on the simulation model. Joint Domain Localized-JDL for global space-time processing and local joint processing based on dimensionality reduction in the presence of ionospheric disturbances. The algorithm is simulated and analyzed. The results show that the JDL algorithm can effectively suppress clutter and find the target in the case of significantly reducing the amount of computation and training sample requirements. Quantitative analysis of different degrees. The influence of different ionospheric pollution on the space-time coupling of first-order sea clutter and the loss of signal to clutter ratio caused by space-time processing. The JDL algorithm is used to suppress the non-uniform first-order sea clutter in the actual background, and the target information of the current range dimension samples to be detected is filtered. The above unit is regarded as the conventional sample data to estimate the clutter covariance matrix, which can obviously improve the clutter suppression performance of the target and its local area, combined with the idea of weighted training samples. The output of the distance dimension is taken as the weight given to each training sample. The weighted training samples are reintroduced into the estimation of covariance matrix and the theoretical space-time distribution of first-order sea clutter is used as prior knowledge in the space-time processing algorithm. No target filtering is carried out on the known clutter region. The improved JDL algorithm can significantly increase the depth of the space-time notch in the clutter region, and the improved JDL algorithm can significantly improve the input-output signal-to-clutter ratio in the actual target detection.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN958.93

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