分布式小卫星MIMO-SAR超高分辨成像方法

doi:10.19665/j.issn1001-2400.2021.02.013

摘要/Abstract

摘要：

针对分布式小卫星多发多收合成孔径雷达的聚束工作模式,提出了一种超高分辨成像方法,降低了多通道高分辨率模式下卫星的存储压力以及成像负荷。该方法首先将各通道的全孔径信号划分为子孔径信号;然后对子孔径信号进行解模糊处理,并利用改进的时域带宽合成方法获得大带宽信号;再使用子孔径图像相干融合算法获得超高分辨率图像。仿真实验表明,改进的时域带宽合成方法能够有效地合成带宽,并且所提方法的成像效果良好。

关键词: 合成孔径雷达, 小卫星, 多发多收, 聚束, 子孔径

Abstract:

Aiming at the spotlight mode of the distributed small satellite multiple-input multiple-output synthetic aperture radar(MIMO-SAR),an ultra-high resolution imaging method is proposed to reduce the storage pressure and imaging load of the satellite in a multi-channel high-resolution mode.The full-aperture signal of each channel is divided into sub-aperture signals.The sub-aperture signal is deblurred,and then the large bandwidth signal is obtained by using the improved time domain bandwidth synthesis method.Then the sub-aperture image coherent fusion algorithm is used to obtain the ultra-high resolution image.Simulation results show that the improved time domain bandwidth synthesis method can synthesize bandwidth effectively,and the imaging effect of the proposed method is excellent.The validity and reliability of the method are verified.

Key words: synthetic aperture radar, small satellite, multiple input multiple output, spotlight, sub-aperture

中图分类号:

TN957

杨军,周芳. 分布式小卫星MIMO-SAR超高分辨成像方法[J]. 西安电子科技大学学报, 2021, 48(2): 99-108.

YANG Jun,ZHOU Fang. Ultra-high resolution imaging method for the distributed small satellite MIMO-SAR[J]. Journal of Xidian University, 2021, 48(2): 99-108.

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参数	值	参数	值	参数	值
卫星个数	3	步进频率/MHz	500	子孔径个数	8
平台速度/(m·s^-1)	7 391	脉冲重复频率/MHz	5 000	中心频率/GHz	9.6
场景中心距/km	617	信号带宽/MHz	500	方位基线距离/m	500

点目标	距离向		方位向
点目标	峰值旁瓣比	积分旁瓣比	峰值旁瓣比	积分旁瓣比
P₁	-13.60	-10.35	-13.23	-9.87
P₂	-13.61	-10.37	-13.23	-9.77
P₃	-13.33	-9.75	-13.88	-10.71