线性调频近程探测干扰分析与抗干扰信号处理电路设计

发布时间：2018-04-02 10:52

本文选题：三角波调频　切入点：测距测速　出处：《南京理工大学》2017年硕士论文

【摘要】：线性调频近程探测系统具有无距离盲区、低发射功率、结构简单等特点,广泛应用于各个领域,尤其是军事领域。现代战场电磁环境复杂,人为干扰下的系统性能和抗干扰方法成为研究重点。本文主要包括三角波调频近程探测系统干扰分析与抗干扰信号处理技术研究。首先理论分析了三角波调频探测系统的差频信号,研究了基于线性调频Z变换(Chirp Z Transform,CZT)的测距和基于动目标检测(Moving Target Detection,MTD)的测速算法,通过仿真对算法进行了验证。其次研究了调幅干扰和调频干扰对系统的干扰机理,仿真结果表明调幅干扰和调频干扰在特定参数下均会使系统测距测速性能恶化。根据干扰信号特性提出基于分数阶傅里叶变换(Fractional Fourier Transform,FrFT)的抗干扰算法,仿真结果表明在信干比达到-10dB时仍可以有效抑制噪声调幅干扰、三角波调幅干扰和部分噪声调频干扰。然后根据指标要求完成系统信号处理软硬件设计,硬件设计包括信号处理板的设计、加工、焊接和调试。软件设计为信号处理整体方案的可编程逻辑阵列(Field Programmable Gate Array,FPGA)实现,包括算法离散形式推导、程序编写编译和功能验证。最后将信号处理电路和前端射频天线构成完整系统,完成外场测距测速实验和抗干扰实验。无干扰条件下,外场实测测距和测速误差均在系统指标允许范围内。施加干扰后通过抗干扰算法大大降低测距测速误差,达到系统指标要求。
[Abstract]:The linear frequency modulation (LFM) short-range detection system is widely used in various fields, especially in military field, because of its characteristics of no blind area, low transmitting power, simple structure, etc. The electromagnetic environment of modern battlefield is complex. The system performance and anti-jamming methods under artificial interference have become the focus of research. This paper mainly includes interference analysis and anti-jamming signal processing technology of triangular wave FM short-range detection system. Firstly, the theory analysis of triangular wave FM detection is given. The differential frequency signal of the measuring system, The algorithm of ranging based on Chirp Z transform and moving Target detection based on moving target is studied. The algorithm is verified by simulation. Secondly, the interference mechanism of AM jamming and FM jamming to the system is studied. The simulation results show that both AM jamming and FM jamming can worsen the range measurement performance of the system under certain parameters. According to the characteristics of the jamming signal, an anti-jamming algorithm based on fractional Fourier transform (Fractional Fourier transform) is proposed. The simulation results show that noise AM interference, triangular wave AM interference and partial noise FM interference can be effectively suppressed when the signal-to-interference ratio reaches -10dB, and then the hardware and software design of the system signal processing is completed according to the requirements of the index. The hardware design includes the design, processing, welding and debugging of the signal processing board. Finally, the signal processing circuit and the front-end RF antenna are formed into a complete system to complete the field ranging and velocity measurement experiment and anti-jamming experiment. The error of ranging and velocity measurement in the field is within the allowable range of the system index, and the anti-jamming algorithm can greatly reduce the error of ranging and velocimetry after the interference is applied, so as to meet the requirements of the system.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN911.7

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