组合编码信号波形设计及仿真
发布时间:2018-05-20 13:20
本文选题:组合编码信号 + 随机序列线性调频信号 ; 参考:《电子科技大学》2014年硕士论文
【摘要】:本文主要进行了组合编码信号的波形设计与信号处理方面的研究。波形设计设是雷达系统的关键技术之一,直接影响系统的分辨力、测量精度、抑制杂波以及抗干扰等性能。近年以来,随着数字处理技术发展,为新体制探测技术和雷达波形捷变技术应用提供了可能,因为常规雷达波形样式各有缺陷,需要研究一种具备丰富码元资源和良好探测性能的新型波形样式。首先,介绍了雷达经典理论,如距离分辨率、脉冲压缩技术、多普勒敏感性等,为本文提供了理论基础。本文总结了传统雷达波形的性能特点,以及近年来人们在组合编码信号设计领域的研究状况,对现有的组合编码波形构筑方法进行了归纳总结,并通过数字仿真分析了常见组合编码信号性能及优缺点。在此基础上,作者选择了一种新型随机序列线性调频信号波形样式,并通过数字仿真分析了其各项信号特征,包括频谱分布、脉冲压缩、多普勒敏感,互相关特性。通过研究发现随机序列线性调频信号如采用传统脉冲压缩方式,其探测性能上存在缺陷,无法进入实用。为了发挥随机序列线性调频信号的潜力,本文进一步研究了专用处理方法,提出序列重排和分段积累消差两种新型处理方法,通过数字处理弥补了随机序列线性调频信号的性能缺陷,大幅提升了随机序列线性调频信号的探测性能。序列重排处理方法参考了合成孔径雷达CS算法,在CS算法中,采用频域校正方法消除了地物回波的距离走动,我们将其引入随机序列线性调频信号处理,在信号脉冲压缩前在频域进行码元序列位置移动,将随机序列线性调频信号5重构为标准序列线性调频信号,再进行脉压处理,从而有效降低了脉压旁瓣,提高了探测能力。分段积累消差处理方法参考了早期逆合成孔径雷达处理方法,通过分段处理提高了信号多普勒容限,然后根据信号分段脉压后分布特性加入消差处理,大幅降低序列之间的互相关影响,使随机序列线性调频信号具备了较高实用性。除此之外,本文还提出一种采用多样本脉冲压缩的信号处理思路。利用数字信号处理能力提升,可以将采集的信号利用多个样本和相应的处理方法进行脉冲压缩处理,再对处理结果进行融合处理,充分发挥各个积累方式的优点,获得优化的探测能。本文还设计搭建一个半实物仿真系统,通过半实物射频试验的方法,验证随机序列线性调频信号的实际性能。仿真实验的结果证明,通过序列重排和分段积累消差处理算法,随机序列线性调频信号可以获得优良的探测性能。最后,对全文进行总结,并展望了随机序列线性调频信号在波形捷变技术和新体制探测技术的应用前景。本文的研究成果对开展雷达波形设计的研究具有一定的意义。
[Abstract]:In this paper, the waveform design and signal processing of combined coded signals are studied. Waveform design is one of the key technologies of radar system, which directly affects the system resolution, measurement accuracy, clutter suppression and anti-jamming performance. In recent years, with the development of digital processing technology, it is possible to apply the new system detection technology and radar waveform agile technology, because the conventional radar waveform patterns have their own defects. A new waveform pattern with rich symbol resources and good detection performance needs to be studied. Firstly, the classical theory of radar, such as range resolution, pulse compression, Doppler sensitivity and so on, is introduced, which provides a theoretical basis for this paper. This paper summarizes the characteristics of traditional radar waveforms and the research status in the field of combinatorial coding signal design in recent years, and summarizes the existing methods of constructing combined coding waveforms. The performance, advantages and disadvantages of common combined coded signals are analyzed by digital simulation. On this basis, the author chooses a new type of random sequence LFM signal waveform, and analyzes its signal characteristics by digital simulation, including spectrum distribution, pulse compression, Doppler sensitivity and cross-correlation characteristics. It is found that the detection performance of the LFM signal with random sequence, such as the traditional pulse compression method, is defective and can not be applied. In order to give full play to the potential of random sequence LFM signals, this paper further studies the special processing methods, and proposes two new processing methods, sequence rearrangement and piecewise accumulation cancellation. Digital processing makes up for the performance defect of random sequence linear frequency modulation (LFM) signal and greatly improves the detection performance of random sequence LFM signal. The sequence rearrangement method refers to the synthetic Aperture Radar (SAR) CS algorithm. In the CS algorithm, the range walk of the echo is eliminated by using the frequency domain correction method, which is introduced into the random sequence linear frequency modulation (LFM) signal processing. The position of symbol sequence is moved in the frequency domain before pulse compression. The random sequence LFM signal 5 is reconstructed into a standard sequence LFM signal, and then processed by pulse compression, which effectively reduces the sidelobe of pulse compression and improves the detection ability. The piecewise accumulation cancellation method refers to the early inverse synthetic Aperture Radar processing method. The Doppler tolerance of the signal is improved by the piecewise processing, and then the cancellation process is added according to the distribution characteristics of the signal segments after pulse compression. The cross-correlation between the sequences is greatly reduced, which makes the linear frequency modulation signals of random sequences more practical. In addition, a new method of signal processing using multi-sample pulse compression is proposed. With the improvement of digital signal processing ability, the collected signal can be processed by pulse compression with multiple samples and corresponding processing methods, and then the processing results can be fused to give full play to the advantages of each accumulation mode. The optimized detection energy is obtained. A hardware-in-the-loop simulation system is designed and built in this paper to verify the practical performance of random sequence LFM signals by the method of semi-physical RF test. The simulation results show that the random sequence LFM signal can obtain good detection performance through sequence rearrangement and piecewise accumulation cancellation algorithm. Finally, the application prospect of random sequence linear frequency modulation (LFM) signal in waveform agility and new detection technology is prospected. The research results of this paper have a certain significance for the research of radar waveform design.
【学位授予单位】:电子科技大学
【学位级别】:硕士
【学位授予年份】:2014
【分类号】:TN957.51
【参考文献】
相关期刊论文 前1条
1 孙东延,陶建锋,付全喜;用于低截获概率雷达的混合波形研究[J];航天电子对抗;2001年03期
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