【作者】 王莹；

【导师】 陈涛；

【作者基本信息】 哈尔滨工程大学 ， 通信与信息系统， 2014， 硕士

【摘要】 电子对抗技术在现代信息战中的重要性日益增加,雷达信号的接收和处理是电子对抗技术的研究热点。随着雷达技术的不断发展,现代电磁环境日益复杂,面对信号密集、形势复杂、参数变化快的信号环境,要求电子战接收机具有频率覆盖范围广、灵敏度高、动态范围大、多信号并行处理且满足信号实时性的能力。针对被动雷达信号处理系统的设计,考虑到信道化结构设计和后端信号处理方面,提出了针对宽带中频信号的高精度、实时的信号处理系统设计方案。所设计的宽带中频信号处理系统主要应用在被动雷达系统中,以侦查主动雷达为目标,截获雷达信号后给出信号的相位、频率、信号类型等,并对信号进行测向来确定目标雷达的方位角和俯仰角。在方案设计中,数据采集和信号处理的因素制约着系统性能向更优的方向发展,随着信号带宽的增加,采样率过高不仅对ADC的采样速度和精度提出了更高要求,而且对后端信号处理以及系统设计造成了困难。为了解决上述问题,将传统的测频、测向技术与数字信号处理技术结合起来,采用高精度且采样速度快的ADC及高速FPGA使系统具有精度高、分辨力高、识别能力强等优点。宽带模拟信号首先经过模数转换,信道化过程对高速的数字信号进行降速处理,使得高速采样的宽带信号与FPGA信号处理速度匹配,根据信道化输出的信号IQ信息,得到信号的相位、幅度、频率等,进而进行宽带信号测向和脉内调制特征识别。论文研究的主要内容及创新点如下:首先,本文对宽带中频信号处理系统的关键技术进行研究,推导基于多相滤波的高效信道化结构,仿真验证了该结构的正确性,并且分析了常用的测频算法的测频性能。针对宽带信号的测向问题,本文提出了基于信道化的双频解模糊算法,将宽带信号测向问题与信道化方法进行结合,提高了宽带信号的测向精度。其次,雷达信号的类型识别是雷达信号处理的关键问题,分析了常见的雷达信号类型,针对调频信号和调相信号的脉内特征提出类型识别方法。并提出了V型调频信号和S型调频信号的识别方法,这也是本文的创新点。再次,采用了 ADC和FPGA构建了宽带中频信号处理系统的硬件设计,给出了FPGA的软件设计流程,实现了对宽带中频信号的实时处理,处理时间在10μs以内。最后,在宽带中频信号处理系统硬件测试平台上对其性能进行测试,给出测试结果。更多还原

【Abstract】 Electronic countermeasure technology becoming more and more important in modern information warfare where receiving and processing of radar signals is a research hotspot.With the development of radar technology, the complexity of modern electromagnetic environment is increased, signal environment is intensity, the situation is complex and parameter is fast changing. This requires that the digital receiver must have wide frequency range, high sensitivity, large dynamic range, multi-signal parallel processing and real-time signal processing capacity are essential.In this paper,the design is based on passive radar signal processing system and discussed from the structural design of channelized receiver and process signal of the rear-end in order to put forward a design scheme in which channelized receiver is wideband,high sensitivity and large dynamic range. Wideband intermediate frequency signal processing system is mainly used in the passive radar system, the goal is to detect active radar after acquisition radar signal for giving the phase, frequency and type of the signal by finding direction of signal to determine the location information of target radar. In the design, the factors of data capture and signal process restrict the development of wideband digital receiver. With the increase of the signal bandwidth, the high sample rate made stringent requirements which are not only for speed and precision of ADC, but also for back-end signal processing and for the difficult design of whole system.In order to solve the above problems, this paper combine traditional finding and frequency measurement with digital signal processing technology, using ADC of high sampling speed, high precision and FPGA of high speed so that wideband digital channelized receiver have advantages of high accuracy, high resolution, and strong ability to identify and so on. Wideband signals are firstly through ADC conversion directly, then channelized processing by digital receiver to solve the bottleneck problems of high speed ADC and backend signal processing which is in case of broadband signal receptionb, according to the information of IQ which is output signal of channelized to obtain the phase, amplitude,frequency,then measured direction of broadband signal and recognition the pulse modulation feature.The main contents and innovation of this paper:Firstly, the key technology of passive radar signal processing was studied and the structure of efficient channelized which is based on polyphase filter is derived. Simulations illustrate the correctly of this structure and the frequency measurement algorithms are analyzed. For the problem of wideband signal direction finding,this paper propose a dual frequency defuzzifiedm based on channelized and combine direction finding of wideband signal with channelized, improve the accuracy of wideband signal direction.Secondly, identified the type of radar signals is a key problem in electronic reconnaissance and common radar signals is analyzed. The type identification methods according to different pulse characteristics of frequency modulated signal and phase modulated signal is proposed. The identification method of VFM signal and SFM signal was proposed which is the innovation of this paper.Again, using ADC and FPGA to construct the hardware design of wideband intermediate frequency signal processing system and giving software design processing of FPGA,real-time processing of wideband intermediate frequency signal is realized and procesing time is less than 10us.Finally, the performance of wideband intermediate frequency signal processing system is tested in the hardware test platform and the results are given.更多还原