【作者】 孙长贵；

【导师】 李兴国；

【作者基本信息】 南京理工大学 ， 机械电子工程， 2006， 博士

【摘要】 频率步进雷达是一种频域合成一维距离高分辨雷达，它具有瞬时带宽窄，合成带宽宽，对数据采集和信号处理要求低的特点。雷达的数字化是现代雷达的发展趋势，本论文旨在探索性地研究数字化技术在毫米波高分辨雷达中的应用。论文对数字化技术在雷达中的应用(雷达数字化技术)发展以及雷达数字化技术研究方法进行了全面综述，指出了雷达数字化包括用数字部件代替大部分模拟部件，雷达信号波形的数字化产生、雷达波束的数字化形成、雷达信号的数字化处理等。本论文讨论了使用DDS产生步进频率脉冲和线性调频脉冲复合波形的方法，以及线性调频脉冲频率步进雷达信号的处理方法；应用线性时不变系统理论推导了LFM频率步进雷达信号一维距离像数学表达式；在设计毫米波高分辨雷达导引头时，采用大时宽带宽积脉冲(4μs×31.25MHz)和较窄矩形子脉冲(125ns)频率步进脉冲两种波形，很好地解决了脉冲体制下远程探测与减小近程盲区的矛盾，提出了应用脉内和脉间两种调制波形的方案，兼顾对目标进行远距离和近距离高分辨探测，扩大了毫米波高分辨雷达的作用范围。采用数字直接下变频(DDC)技术，在带通采样过程中，同时完成下变频，降低了工程实现的难度。计算并优化了毫米波雷达中频信号带通采样的最佳采样频率，应用现有的集成电路技术实现对中频信号的直接采样、用一个A／D转换器在数字域完成复数正交变换，在数字域完成下变频、获得同相信号和正交相信号、完成对子脉冲的脉内压缩、完成对脉内压缩信号的第二次脉间压缩，从而获得高分辨一维距离像。提出了二步伸缩处理方法，在测距的同时，做到测速，有利于一维成像的速度补偿。论文在理论研究的基础上，进一步研究了DDS的控制方法，用单片机对DDS芯片进行控制，产生线性调频基带脉冲(Chirp)，结合步进频率脉冲的方法，实现两种波形之间的自适应切换，给出了实验结果。提出了Costas调频编码脉冲的DDS实现方案。更多还原

【Abstract】 Stepped Frequency Radar (SFR) is a type of one dimension high range resolution radarprovided with wideband by using frequency-field- synthesizing method. It characterizesinstantaneous narrow band signal, but synthesized wide-band signal, thus makes dataacquisition and signal processing easier.Radar digitization is a trend of radar development. Application study of digital techniqueapplied in millimeter wave high resolution radar is a necessary requisition of modern radartechnique.This dissertation gives a completely survey to digital technique application in radar (radardigitization technique) and the technological research approach of radar digitization. Itpoints out that radar digitization includes replacing analog components with digitalalternatives, digital signal generation、digital beam forming and digital signal processing,etc.This dissertation presents a new method of generating complex waveforms of frequencystepped pulse and CHIRP with DDS technology. When designing the MMW HRR homingsystem, CHIRP wave form with great time-bandwidth product(125) and short time pulseare used in the same system to solve the incompatible problem of long rafige detection andshort range blind area, greatly enlarge the radar homing system’s operating scope. Whenadopting Digital Down Conversion (DDC), in the band pass sampling process millimeterwave down conversion is made at the same time, so made it easy to realize in engineering,The optimum sampling frequency of band pass sampling are calculated and optimized. Soby using the state-of-art integrated circuit MMW direct sampling is realized. Only oneA/D converter is needed to complete complex quadrature translation and digital downconversion, get in-phase component and quadrature component in digital field, and also,after intra-pulse compression is done, the signal-to-noise ratio is raised, and inter-pulsecompression is done in digital field, and finally, high range resolution profile is got.Two-step stretch processing method for MMW high-resolution RADAR is presented.On the basis of theoretical research, this dissertation presents control method of DDSdevice, control. DDS chip with a microcontroller, produce the baseband pulse of linearfrequency modulation (Chirp), integrate stepped-frequency pulse with Chirp, realizeself-adaptation switch-over between two kinds of wave forms, and experimental resultsare presented. Implementation of inter-pulses costas FH high resolution MMW radarsignal using dds technology is included.更多还原