基于空时相位编码的MIMO-SAR回波分离方案

魏屹海; 叶新魁; 张永伟; 刘洋; 王伟; 王沛

doi:10.12000/JR25148

基于空时相位编码的MIMO-SAR回波分离方案

DOI: 10.12000/JR25148 CSTR: 32380.14.JR25148

魏屹海^{1, 2},
叶新魁³,
张永伟^1, ,,
刘洋¹,
王伟^{1, 2},
王沛^1, ,

1.
中国科学院空天信息创新研究院北京 100094
2.
中国科学院大学电子电气与通信工程学院北京 100049
3.
中国人民解放军91715部队广州 510000

基金项目: 国家重点研发计划 (2023YFB3904901)

详细信息

作者简介:
魏屹海，博士生，主要研究方向为多发多收合成孔径雷达、波形设计、雷达信号处理等

叶新魁，硕士，工程师，主要研究方向为雷达与通信信号处理

张永伟，博士，副研究员，主要研究方向为高分宽幅SAR、波形设计、MIMO SAR等

刘　洋，硕士，助理研究员，主要研究方向为SAR信号产生、高速电路设计

王　伟，博士，研究员，博士生导师，主要研究方向为星载微波成像系统体制与信号处理技术

王　沛，博士，研究员，博士生导师，主要研究方向为合成孔径雷达系统设计及宽带信号处理技术

通讯作者:
张永伟 zhangyw01@aircas.ac.cn

王沛 wangpei@aircas.ac.cn

责任主编：李宁 Corresponding Editor: LI Ning
中图分类号: TN959.74
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出版历程
- 收稿日期: 2025-08-01

Novel Space-Time Phase-Coded Echo Separation Method for MIMO SAR

WEI Yihai^{1, 2},
YE Xinkui³,
ZHANG Yongwei^{1
, ,},
LIU Yang¹,
WANG Wei^{1, 2},
WANG Pei^{1
, ,}

1.
Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, China
2.
School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences; Beijing 100049, China
3.
The 91715th Unit of the People's Liberation Army of China; Guangzhou 51000, China

Funds: National Natural Key Research and Development Program of China under Grant (2023YFB3904901)

More Information

Corresponding author: ZHANG Yongwei, zhangyw01@aircas.ac.cn; WANG Pei, wangpei@aircas.ac.cn

摘要

摘要: 高分辨率宽幅(HRWS)成像是未来星载合成孔径雷达(SAR)系统的重要发展方向。多发多收(MIMO)SAR系统具备更高的空间自由度，具有进一步增强系统性能的潜力。然而有效实现MIMO-SAR中不同发射通道回波的分离，是发挥其空间自由度优势的关键前提。该文基于SAR体制中所采用信号的相位特性，以及“走-停”模型中空间—时间特性，设计一种适用于MIMO-SAR体制的新型空时相位编码(STPC)波形。该波形通过相位编码对发射信号在距离向进行调制，并依据预设的编码调制序列，在每个脉冲周期内的不同空间位置处进行信号发射。接收时基于与发射端匹配的编码调制时序，对混叠回波进行解调处理，可实现不同发射通道回波的高效分离。所提方案能够与现有经典的方位多通道重构方法结合，有效缓解了脉冲重复频率(PRF)与回波可分离性之间的矛盾。与现有MIMO-SAR系统中的Alamouti波形、短偏移正交(STSO)波形、分段相位编码(SPC)波形相比，所需天线资源减少近一半，降低了系统硬件实现成本与复杂度。最后，通过点目标与分布场景的仿真实验证明所提波形及处理方案能够有效抑制不同波形之间的干扰信号，具有良好的成像性能。
- 合成孔径雷达 /
- 多发多收 /
- 相位编码 /
- 回波分离 /
- 波形设计
Abstract: High-resolution wide-swath imaging is a key development direction for next-generation spaceborne synthetic aperture radar (SAR) systems. Multiple-input multiple-output (MIMO) SAR systems offer high spatial degrees of freedom, enabling enhanced system performance. However, effectively separating echoes from different transmit channels in MIMO-SAR systems is key to unlocking their advantages in spatial degrees of freedom. In this regard, a novel space-time phase-coded (STPC) waveform for MIMO-SAR systems is proposed based on the phase characteristics of SAR signals and the space-time properties of the “stop-and-go” model. This waveform modulates transmitted signals in the range dimension via phase coding and emits them at distinct spatial positions within each pulse repetition period, following a preset coding sequence. Upon reception, demodulating aliased echoes using receiver timing matched to the transmitter enables the efficient separation of echoes from different transmit channels. The proposed scheme can be integrated with existing classical azimuth multichannel reconstruction methods, effectively mitigating the trade-off between pulse repetition frequency and echo separability. Compared with the Alamouti, short-term shift-orthogonal, and segmented phase code waveforms in current MIMO-SAR systems, the STPC approach reduces antenna requirements by nearly 50%, thereby lowering the cost and complexity of hardware implementation. Simulation experiments on point targets and distributed scenes verify that the proposed waveform and processing scheme effectively suppress interwaveform interference and deliver strong imaging performance.
- Synthetic Aperture Radar(SAR) /
- Multiple-Input Multiple-Output (MIMO) /
- Phase Encoding /
- Echo Separation /
- Waveform Design

HTML全文

图 1 MIMO-SAR成像几何模型与系统相位中心示意图

Figure 1. Geometric model of MIMO-SAR imaging and schematic diagram of system phase center

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图 2 基于空时编码的MIMO-SAR发射-接收构型

Figure 2. MIMO-SAR Transmit-receive configuration based on Space-time coding

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图 3 MIMO-SAR成像几何构型示意图

Figure 3. Schematic diagram of MIMO-SAR imaging geometry configuration

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图 4 MIMO信号生成时序图

Figure 4. Timing diagram of MIMO signal generation

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图 5 MIMO-SAR系统中空时相位编码信号传输过程流程图

Figure 5. Flowchart of the transmission process of space-time phase-coded signals in the MIMO-SAR system

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图 6 主要处理流程框架图

Figure 6. Main processing procedure

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图 7 混叠回波重排序列图

Figure 7. aliased echo reordering sequence diagram

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图 8 回波分离处理中混叠信号方位向相位中心示意图

Figure 8. Schematic diagram of the azimuth phase center of the aliased signal in the echo separation processing

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图 9 点目标成像场景示意图

Figure 9. Simulation scene of point targets

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图 10 情况一两组波形点目标二维仿真结果

Figure 10. 2D Simulation results of point targets using two sets of waveforms in Case 1

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图 11 情况二两组波形点目标二维仿真结果

Figure 11. 2D Simulation Results of Point Targets Using Two Sets of Waveforms in Case 2

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图 12 两个发射通道6个接收通道的MIMO-SAR分布式场景仿真成像结果

Figure 12. Simulation imaging results of MIMO-SAR distributed scenarios with two transmitting channels and six receiving channel

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图 13 场景一信号能量分布

Figure 13. The signal energy distribution in Scene 1

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图 14 信号分离指标随相位误差变化情况

Figure 14. The variation of signal separation metrics with phase error

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图 15 STSO方案与本文所提STPC方案的回波分离结果

Figure 15. Echo separation results of STSO scheme and the STPC scheme proposed in this paper

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表 1 星载MIMO-SAR系统参数

Table 1. Parameters of spaceborne MIMO-SAR system

参数	指标
系统载频	9.6 GHz
俯仰向天线长度(m)	4
方位向天线长度(m)	15
信号带宽(Mhz)	40
信号时宽(μs)	10
多普勒带宽(Hz)	3003
系统脉冲重复频率(Hz)	2402
平台高度(Km)	700
卫星速度(m/s)	7507
下视角(°)	23°～ 26°
方位向通道数量	3
俯仰向通道数量	2
发射机个数	2
信号类型	正负调频信号

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表 2 场景二回波分离指标分析

Table 2. Echo separation index analysis of Scene 2

参数	参考指标	图12(c)	图12(e)	图12(g)
对比度	0.4487	0.8710	0.4491	0.4523
MSE	217259048	106590879	216356821	214995539
NCC	0.2666	–0.0328	0.2648	0.3239

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表 3 回波分离所需天线数量比较

Table 3. Comparison of the number of antennas required for echo separation

MIMO-SAR方案	天线数量
Alamouti-STC方案	M
STSO方案	2M-1
SPC方案	2M-1
OFDM方案	2M-1
所提STPC方案	M

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