基于线性功放的数字阵列雷达多波束形成技术研究

发布时间：2018-04-30 10:42

本文选题：数字阵列雷达 + 发射数字多波束　；参考：《电子科技大学》2016年硕士论文

【摘要】：现代信息化战争要求雷达必须具备高的搜索速率、高的多普勒分辨率和角分辨率、高抗干扰能力和同时多功能(如搜索与跟踪)等。数字阵列雷达收发均采用数字波束形成(DBF)技术,可以快速改变波束指向和形状,容易形成多个波束等,可以很好的满足上述需求,研究发射数字多波束技术具有十分重要的意义。本文以数字波束形成原理为基础,深入研究了发射数字多波束的原理及实现方法。以和波束功率方向图为重要工具,通过理论分析和仿真,详细研究了系统参数、通道间幅相不一致性及功率放大器对发射多波束的影响。本文的主要工作包括以下几个方面:1.介绍了数字阵列雷达的研究背景及意义,回顾了数字阵列雷达的历史和现状,进而阐明了数字阵列雷达发射数字多波束的意义。2.以数字波束形成为基础,介绍了发射数字多波束的原理,讨论了三种发射数字多波束实现方法:数字配相法,IFFT法和正交投影法。分析三种算法的原理和特点,得到了正交投影法更适合用于数字阵列雷达发射多波束的结论。3.给出了分析发射多波束性能的重要工具:和波束功率方向图。利用和波束功率方向图研究了系统参数对发射多波束的影响,分析了不同实现算法的特点,验证了正交投影法可在干扰方向形成很深的零陷,具有更好的波束间隔离度。通过研究发射信号、有限字长对和波束方向图的影响发现:相干信号会使发射多波束彼此干扰;数字信号处理时有限字长量化位数越多,其实际发射多波束效果越好。4.研究了多通道间幅相不一致性对发射多波束性能的影响,讨论了在有幅相误差时,波束图在不同算法下的失真特点,发现在不同的算法下,波束失真特性不同,且在幅度误差和相位误差下失真特点各不相同。分析了通道失配对加窗效果的影响,得到了通道失配会破坏加窗作用的结论。5.基于功率放大器的非线性数学模型,研究了功放对发射信号及多波束形成的影响,由理论分析及仿真结果得知,无记忆功放输出信号特性与输入信号包络是否恒定有关;有记忆功放在输入功率较小时记忆性作用更明显,而在输入功率较大时非线性作用更显著,为进一步实现预失真等线性化技术提供了技术支持。
[Abstract]:Modern information warfare requires radar to have high search rate, high Doppler resolution and angular resolution, high anti-jamming ability and multi-function (such as search and tracking). Digital array radar transceivers adopt digital beamforming (DBF) technology, which can quickly change the direction and shape of the beam, and easily form multiple beams, which can meet the above requirements. It is very important to study the technology of transmitting digital multi-beam. Based on the principle of digital beamforming, the principle and implementation of transmitting digital multi-beam are studied in this paper. With the power pattern of sum beam as an important tool, the effects of system parameters, amplitude and phase inconsistency between channels and power amplifier on transmitting multi-beam are studied in detail by theoretical analysis and simulation. The main work of this paper includes the following aspects: 1. This paper introduces the research background and significance of digital array radar, reviews the history and present situation of digital array radar, and expounds the significance of digital array radar transmitting digital multi-beam. On the basis of digital beamforming, this paper introduces the principle of transmitting digital multi-beam, and discusses three realization methods of transmitting digital multi-beam: digital phase matching method, Ifft method and orthogonal projection method. The principle and characteristics of the three algorithms are analyzed, and the conclusion that orthogonal projection method is more suitable for digital array radar transmitting multi-beam is obtained. An important tool for analyzing the performance of transmitting multi-beam is given: and the beam power pattern. The influence of system parameters on transmitting multi-beam is studied by using and beam power pattern. The characteristics of different implementation algorithms are analyzed. It is verified that orthogonal projection method can form deep zero trapping in the direction of interference and has better isolation between beams. By studying the effect of finite word length on beam pattern, it is found that coherent signal will interfere with each other in transmitting multi-beam, and the more quantized bits with finite word length in digital signal processing, the better the effect of transmitting multi-beam. The effect of amplitude and phase inconsistency between multiple channels on the performance of transmitting multi-beam is studied. The distortion characteristics of beam map under different algorithms are discussed when there is amplitude and phase error. It is found that the distortion characteristics of beam are different under different algorithms. The distortion characteristics are different under amplitude error and phase error. The effect of channel mismatch on the effect of window addition is analyzed, and the conclusion that channel mismatch will destroy the effect of window addition is obtained. Based on the nonlinear mathematical model of power amplifier, the influence of power amplifier on transmitting signal and multi-beam forming is studied. The theoretical analysis and simulation results show that the characteristic of output signal of memoryless amplifier is related to whether the envelope of input signal is constant or not. The effect of memory power amplifier is more obvious when the input power is small, and the nonlinear effect is more obvious when the input power is high, which provides technical support for further linearization technology such as pre-distortion.
【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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