车载MIMO雷达成像技术

论文总字数：27815字

摘 要

对于雷达等军工产品的民用化过程一直在进行，车载雷达一直是其中的一个热门的研究方向。与其他类型的传感器相比，雷达所具有的优势为：全天时、全天候和远距离作用。相比较其他微波频段，毫米波雷达具有更加精准的距离和多普勒分辨能力。当今社会，毫米波雷达在自动辅助驾驶中扮演着重要的角色。本文的主要研究对象是车载MIMO雷达。在角度分辨率方面，MIMO雷达相比于传统的雷达具有更高的角度分辨率。相应的，本文对车载MIMO雷达的成像原理和算法理论进行研究。

本文主要研究了车载MIMO雷达的成像原理，利用MIMO雷达的FDA体制设计多分集信号发射与回波分离，实现等效大孔径MIMO阵列，并研究波束成形和测角算法，实现对目标的高分辨率。

1. 首先分别研究了OFDM体制和FDA体制基本原理，并简单比较两种不同体制的优缺点，最后发现FDA体制更适合于车载应用。
2. 之后我们结合了FDA的工作原理，分别研究距离-多普勒成像原理和测角算法。在距离测定中，主要研究了不同发射信号的相干化处理。在速度测定中，主要对测速的速度模糊问题以及无模糊范围进行研究。在角度测定中通过DBF和relax算法对角度进行测定。
3. 最后进行仿真实验，其中我们通过对五个目标的仿真，分析仿真结果的差异性，并对同距同速不同角的两个目标进行仿真，发现可以区分出两个目标，验证论文算法的有效性。

关键词： 频率分集阵列、测速测距、多输入多输出阵列、数字波束成形、松弛算法

ABSTRACT

The civilization process for military products such as radar has been ongoing, and vehicle radar has always been one of the hottest research directions. Compared to other types of sensors, radar has the advantages of all-day, all-weather and long-distance. Millimeter wave radar has its own superiority over the ones of other bands, i.e. more accurate two-dimensional Doppler imaging resolution. In today's society, millimeter wave (MMW) radar has an irreplaceable role in automatic assisted driving. The main research direction of this thesis is the in-vehicle MIMO imaging radar. In terms of angular resolution, MIMO radar has higher angular resolution than conventional radar. Correspondingly, this paper studies the imaging principle and algorithm theory of vehicle-mounted MIMO radar.

In this paper, the imaging principle of vehicle-borne MIMO radar is mainly studied. The FDA principle of MIMO radar is used with multi-diversity signal transmission and echo separation to achieve equivalent large aperture array. Beam forming and angle measurement algorithm are also studied to achieve high angle resolution of the target.

1. Firstly, the basic principles of OFDM system and FDA system are studied, and the advantages and disadvantages of the two systems are simply compared. Finally, it is found that FDA system is more suitable for vehicle applications.

2. After that, we combined the working principle of FDA and studied the range-Doppler imaging and angle estimation algorithm respectively. In distance measurement, the range processing of and separation between FDA signals from different transmitters is mainly studied. In the speed measurement, the speed ambiguity problem and the non-ambiguous speed are analyzed. In angle measurement, the DBF and relax algorithms are used to measure the angle.

3. Finally, the experiment is performed using simulation data. We analyze the difference of the simulation results by simulating five targets, and simulate two targets at the same distance, at the same speed and at different angles. We find that two targets can be distinguished.

Keywords: FDA, speed ranging, MIMO array, DBF, RELAX

目 录

摘要 I

ABSTRACT II

第一章 绪论 1

1.1研究背景和发展概述 1

1.2 研究现状^[3] 2

1.3 研究内容和章节安排 4

第二章 车载MIMO雷达体制设计 6

2.1 OFDM体制 8

2.1.1 OFDM原理及MIMO雷达信号处理 8

2.1.2 OFDM的匹配滤波以及实验验证 9

2.2 FDA体制 12

2.2.1频率分集阵列雷达模型^[11] 12

2.2.2频率分集阵列接收^[12] 14

2.2.3 频率分集阵列仿真实验 17

2.3本章小节 19

第三章 车载MIMO雷达成像算法研究 20

3.1 测距 20

3.2 测速 23

3.3 MIMO测角 26

3.3.1MIMO阵列模型 27

3.3.2DBF算法^[20] 28

3.3.3 RELAX算法 30

3.4 仿真实验及结果分析 31

第四章 本文工作总结和展望 38

4.1 本文工作总结 38

4.2 研究展望 39

参考文献 40

致 谢 42

第一章 绪论

1.1研究背景和发展概述

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