| 摘要: |
| 集中式多输入多输出（Multiple Input Multiple Output，MIMO）雷达通常利用正交波形增加发射波形自由度，采用数字阵列拓展空间收发自由度，使得雷达接收机的天线孔径获得明显扩展，最终带来空间分辨率、测角精确度、杂波抑制能力等大幅度提升。但是，这些性能提升的前提是发射波形具有正交特性。事实上，在实际应用中，在不牺牲时域/频域资源情况下，受限于时宽带宽积，无法获得完全正交的波形集合，从而限制了MIMO雷达系统性能。本文对集中式MIMO雷达正交波形复用的技术原理进行了系统回顾，分别归纳了三种快时间发射波形设计方法：时分复用（Time Division Multiplexing, TDM）、码分复用（Code Division Multiplexing，CDM）和频分复用 （Frequency Division Multiplexing, FDM），以及两种慢时间发射波形设计方法：多普勒分复用（Doppler Division Multiplexing，DDM）和随机相位编码波形，并对其优缺点进行对比。同时，对快时间MIMO和慢时间MIMO的信号处理流程进行归纳综合，给出基于匹配滤波的集中式MIMO雷达统一信号处理框架。为了展示不同波形对成像性能的影响，本文给出了基于三维匹配滤波的MIMO雷达成像结果。最后，结合实际应用问题，指出当前MIMO雷达面临的技术难点和发展趋势。 |
| 关键词: MIMO雷达 正交波形 时分复用 码分复用 频分复用 多普勒分复用 |
| DOI：DOI:10.3969/j.issn.1672-2337.2023.01.001 |
| 分类号:TN958；TN957.51 |
| 基金项目:国家杰出青年基金项目（No.61925108）；陕西省自然科学基础研究计划一般项目-面上项目（No.2023?JC?YB?573）；中央高校基本科研业务费（No.D5000210641） |
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| A Review of Orthogonal Waveform Design and Signal Processing in Colocated MIMO Radar |
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HUANG Lei, LIU Aifei, GAO Caicai
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1. College of Electronics and Information Engineering, Shenzhen University, Shenzhen 518000， China;2. School of Software, Northwestern Polytechnical University, Xi’an 710129, China;3. China Communication Microelectronics Technology Co Ltd, Shenzhen 518100, China
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| Abstract: |
| In colocated multiple input multiple output(MIMO) radar, orthogonal waveforms are commonly employed to increase the degrees?of?freedoms (DOFs) of transmit waveforms, and digital array techniques are adopted to augment the DOFs of transmitters and receivers, eventually leading to a virtual array at receivers which significantly expends the aperture. Therefore, colocated MIMO radar is able to improve spatial resolution, estimation accuracy, and clutter suppression. However, the aforementioned theoretical advantages highly depend on the orthogonality of adopted waveforms. As a matter of fact, due to the limited time?bandwidth product, perfect orthogonal transmit waveforms are unavailable in real?world applications without sacrificing the time/frequency domain resources, which in turn degrades the performance of MIMO radar system. This work reviews the typical waveforms for MIMO radar, varying from fast?time time?division?multiplexing (TDM), code?division?multiplexing (CDM), to frequency?division?multiplexing (FDM) MIMO waveforms, slow?time Doppler?division?multiplexing (DDM) and slow?time random phase?coded waveforms, and compares their pros and cons. In addition, we have summarized the signal processing of fast?time and slow?time MIMO radars and provided a unified signal processing frame which is suitable for both fast?time and slow?time MIMO radars. Simulation results are provided to demonstrate the detection performance of MIMO radar with different waveform designs in 3?D matched filtering. Moreover, from the perspective of real?world applications, this paper reviews the practical issues and trends of MIMO radar. |
| Key words: MIMO radar orthogonal waveforms time division multiplexing (TDM) code division multiplexing (CDM) frequency division multiplexing (FDM) Doppler division multiplexing (DDM) |
