雷达信号检测与解距离模糊技术的研究与实现

发布时间：2018-01-18 12:14

本文关键词：雷达信号检测与解距离模糊技术的研究与实现　出处：《西安电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：PD雷达是一种全相参体制的雷达,在现代雷达体系中占有非常重要的地位,它利用较高的积累脉冲数来提高信噪比,提高雷达的检测效果。雷达接收到的回波中包含目标回波、噪声和杂波等,检测的任务是将目标从杂波中区分出来,并获得目标的距离、速度等信息。雷达检测系统通常包含MTI、MTD、恒虚警检测、脉冲积累、噪声检测、解距离模糊等部分。恒虚警检测根据杂波背景的变化提供一个自适应的检测阈值使虚警率维持相对恒定。常见杂波背景的分类有瑞利分布模型、对数正态分布模型、韦布尔分布模型、K分布模型等,他们从不同的擦地角和分辨率对草地、树木、建筑物、雨雪、海浪等杂波进行模拟。本文对瑞利杂波背景下的均值类算法、有序统计类算法进行研究,对这些算法在杂波边缘、多目标环境等表现出的不同检测性能及恒虚警损失进行研究。在PD雷达中,当采用较高的脉冲重复频率时会造成距离模糊,通常利用不同重复频率的脉冲信号对目标真实距离进行求解。首先利用目标在不同的重复周期上的视在距离构成同余方程组,当每个重复周期对应的最大不模糊距离之间是两两既约的整数时,可以求得目标的唯一实际距离。一般情况下,对目标真实距离的求解可以从三个方面进行:一是孙子定理法;二是排列所有的可能值寻找最佳重合点;三是假定目标再对目标进行跟踪。本文对在工程中常用的一维集法、余差查表法等解模糊算法进行研究,并对他们的计算复杂度和冗余性进行分析,最后根据FPGA实现的特点,提供了一种将方差值制成表格的方法,减少了解模糊过程中的计算量,并提高了测量误差的冗余性。本文的最后一部分讲述了在某实际雷达系统中基于FPGA的检测流程的实现。利用FPGA来实现恒虚警检测过程可以实现MTD的多个通道上的数据并行处理,与DSP相比节省了时间,可以实现流水操作;而用FPGA实现改进的一维集算法,省去了对所有可能值排序的过程,将所有误差的可能情况制成表格后也对计算过程大大简化,提高了整个检测流程的效率;通过对实际回波数据的分析,在实际检测流程中采取门限细化的方法,提高了检测效果。
[Abstract]:PD radar is a kind of coherent radar, which plays a very important role in modern radar system. It makes use of higher accumulated pulse number to improve the signal-to-noise ratio (SNR). Radar echo includes target echo noise clutter and so on. The task of detection is to distinguish the target from the clutter and to obtain the distance of the target. Speed and other information. Radar detection systems usually include MTI MTD, CFAR detection, pulse accumulation, noise detection. CFAR detection provides an adaptive detection threshold to keep the false alarm rate relatively constant according to the variation of clutter background. The classification of common clutter background has Rayleigh distribution model. Logarithmic normal distribution models, Weibull distribution models, K distribution models, etc., from different erasing angles and resolutions to grasslands, trees, buildings, rain and snow. In this paper, we study the mean class algorithms and ordered statistical algorithms in Rayleigh clutter background, and study these algorithms on the edge of clutter. The different detection performance and CFAR loss of multi-target environment are studied. In PD radar, the range will be blurred when the pulse repetition frequency is high. The real distance of the target is usually solved by the pulse signal of different repetition frequency. Firstly, the apparent distance of the target in different repetition period is used to form the congruence equations. When the maximum nonfuzzy distance corresponding to each repetition period is a pairwise reduced integer, the unique actual distance of the target can be obtained. The solution of the real distance of the target can be carried out from three aspects: the first is the Sun Tzu Theorem method; The second is to arrange all the possible values to find the best coincidence point; The third is to assume that the target is tracked again. In this paper, the common methods of one-dimensional set method, residual error lookup table and other fuzzy algorithms are studied, and their computational complexity and redundancy are analyzed. Finally, according to the characteristics of FPGA implementation, a method of making the square difference into a table is provided to reduce the amount of calculation in the process of understanding ambiguity. The last part of this paper describes the realization of the detection flow based on FPGA in a real radar system. Using FPGA to realize the CFAR detection process can realize MT. Data on multiple channels of D are processed in parallel. Compared with DSP, it saves time and realizes income operation. Using FPGA to implement the improved one-dimensional set algorithm, the process of sorting all possible values is eliminated, and the calculation process is greatly simplified after all possible errors are made into tables. Improve the efficiency of the whole detection process; Through the analysis of the actual echo data, the method of threshold thinning is adopted in the actual detection flow, and the detection effect is improved.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN957.51

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