相位编码OFDM雷达关键技术的仿真实现及抗干扰性能研究

发布时间：2018-02-21 18:05

本文关键词： 相位编码OFDM 波形设计信号处理抗干扰仿真软件实现　出处：《电子科技大学》2016年硕士论文　论文类型：学位论文

【摘要】：新体制抗干扰雷达和高分辨率雷达成像技术是近几年来雷达领域研究的热点,而相位编码OFDM雷达同时具有较高的距离分辨率和优良的抗干扰性能,因此研究相位编码OFDM雷达关键技术的仿真实现并进一步构建其可视化的仿真软件系统具有一定的实用价值。相位编码OFDM信号,顾名思义,是指对OFDM信号的各个子载波进行合适的相位编码,因此其信号的产生可以和普通OFDM信号一样直接利用IFFT/FFT进行快速的数字调制解调。相位编码OFDM信号具有较大的时宽带宽积,因此雷达可以获得较好的低截获概率性能和较高的距离分辨力。多样的相位编码方式又使得相位编码OFDM雷达的波形设计灵活多变,通过适当的波形设计和优化使得雷达可获得较高的抗干扰性能,因而能够更好地适应复杂的工作环境。本文可分为两个部分,其中第一部分是对相位编码OFDM雷达系统的仿真实现的关键算法进行研究和验证,主要包括以下三个方面的内容：在波形设计方面,首先,本文对相位编码OFDM信号的结构特性、模糊特性和自相关特性进行了详细的分析；然后,分别在巴克码和混沌二相码两种不同的编码方式下,研究了改善信号的自相关性能和峰均功率比的方法；最后,给出一种可行的相位编码OFDM雷达发射信号的设计方式。在信号处理方面,首先,本文阐述了相位编码OFDM雷达系统的信号发射和回波接收过程；然后,针对OFDM信号特殊结构研究了“两级脉冲压缩”方法和相应的目标检测方法。最后,对于目标测距和测速问题,分别采用降低模糊函数周期旁瓣来避免距离模糊的方法和基于“最小二乘”解速度模糊的测速方法。在抗干扰性能方面,本文主要研究的是混沌编码OFDM雷达信号。利用混沌码的初值敏感性产生众多彼此互不相关的编码序列,而雷达发射信号的不同脉冲由不同初值的混沌二相码序列所编码,由此增加了脉冲问的互异性,从而提高了混沌编码OFDM雷达在噪声压制干扰和复制欺骗干扰下的抗十扰性能。第二部分主要介绍了在VC++平台上,相位编码OFDM雷达系统仿真软件的模块化方式的设计与实现。首先,利用已在第一部分完成研究的相位编码OFDM雷达系统的各级实现算法,进行了仿真软件的各级功能模块的设计和实现。然后,完成了对各个主要模块的仿真调试及对整个仿真内核的系统仿真调试。
[Abstract]:The new anti-jamming radar and high-resolution radar imaging technology are the hot spots in the field of radar in recent years, while the phase-coded OFDM radar has high range resolution and excellent anti-jamming performance at the same time. Therefore, it has certain practical value to study the simulation of the key technology of phase-coded OFDM radar and further construct its visual simulation software system. The phase-coded OFDM signal, as its name implies, It refers to the proper phase coding of each sub-carrier of OFDM signal, so its signal can be generated by using IFFT/FFT directly as ordinary OFDM signal to perform fast digital modulation and demodulation. The phase-coded OFDM signal has a large time-bandwidth wide product. Therefore, radar can obtain better performance of low probability of interception and higher range resolution. Various phase coding methods make the waveform design of phase-coded OFDM radar flexible and changeable. Through proper waveform design and optimization, radar can achieve high anti-jamming performance, so it can better adapt to complex working environment. This paper can be divided into two parts. The first part is to study and verify the key algorithms of phase coded OFDM radar system simulation, including the following three aspects: in the aspect of waveform design, firstly, the structural characteristics of phase coded OFDM signal are discussed. The fuzzy and autocorrelation characteristics are analyzed in detail. Then, the methods to improve the autocorrelation performance and the peak-to-average power ratio of the signal are studied under two different coding methods: Barker code and chaotic two-phase code. In the aspect of signal processing, this paper first describes the signal transmitting and echo receiving process of phase coded OFDM radar system. According to the special structure of OFDM signal, the "two-stage pulse compression" method and the corresponding target detection method are studied. The method of reducing the periodic sidelobes of fuzzy function to avoid distance ambiguity and the method of velocity measurement based on least square solution are adopted respectively. In this paper, chaotic coded OFDM radar signals are mainly studied. Using the initial value sensitivity of chaotic codes to generate many discrete coding sequences, the different pulses of radar transmitted signals are encoded by chaotic binary code sequences with different initial values. In this way, the mutual heterogeneity of pulse interferences is increased, and the performance of chaotic coded OFDM radar is improved under noise suppression jamming and duplicated deception jamming. The second part mainly introduces the performance of chaotic coded OFDM radar on VC platform. The design and implementation of modularization of phase coded OFDM radar system simulation software. Firstly, the realization algorithm of phase coded OFDM radar system has been completed in the first part. The design and implementation of the functional modules at all levels of the simulation software are carried out. Then, the simulation debugging of the main modules and the system simulation debugging of the whole simulation kernel are completed.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN958

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