基于脉间捷变频的低空聚束SAR快速成像算法

doi:10.12305/j.issn.1001-506X.2026.07.10

Abstract

Abstract:

A fast polar format algorithm （PFA） based on inter-pulse frequency agility is proposed to address the issue of insufficient anti-jamming capability of low-altitude spotlight synthetic aperture radar in complex electromagnetic environments. Firstly, a wavenumber domain spatially varying phase error model for frequency agility signals is constructed to reveal the failure mechanism of traditional PFA. Secondly, a multi domain joint compensation strategy is proposed: in the time domain, the distance axis carrier frequency joint compensation matrix is used to achieve complete phase compensation of the mainlobe in the distance direction, suppressing the coupling effect of spatially varying errors on sidelobes. An adaptive spectrum recovery function in the wavenumber domain is designed to eliminate azimuth spectrum offset and leakage caused by frequency agility. The simulation results show that the proposed algorithm improves the peak sidelobe ratio and integrated sidelobe ratio of point targets by 13.85 dB and 14.26 dB, respectively, compared to fixed carrier frequency PFA, while retaining PFA computational efficiency and motion adaptability. Moreover, in anti-jamming mode, the amplitude of false targets attenuates to 3.03% of that of real targets. The computational complexity of the proposed algorithm is almost equivalent to that of the fixed carrier frequency PFA, with a processing time increase of only 12.20%. This indicates that the proposed algorithm can provide a solution for low-altitude unmanned aerial vehicle synthetic aperture radar platforms that combines high-resolution real-time imaging and strong anti-jamming capabilities.

Key words: synthetic aperture radar （SAR）, polar format algorithm （PFA）, fast imaging, anti-jamming, inter-pulse frequency agility （IFA）

CLC Number:

TN 974

Zihan JIN, Shuai JIANG, Yanbin LIU, Yue CAO, Zhongjun YU. Low-altitude spotlight SAR fast imaging algorithm based on inter-pulse frequency agility[J]. Systems Engineering and Electronics, 2026, 48(7): 2229-2240.

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References 33

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参数	参数值
载频/GHz	5.4
捷变范围/MHz	200/0 （固定载频）
合成孔径时间/s	1.309 5
波长/m	0.055 6
飞机设计时速/（m/s）	100
发射脉冲宽度/μs	4
信号带宽/MHz	200
斜视角/（°）	0（正侧视）
平台高度/m	800
脉冲重复频率/Hz	1 000

点目标	PSLR		ISLR
点目标	距离向	方位向	距离向	方位向
A点（IFA-PFA）	−24.03	−14.43	−22.56	−10.38
A点（PFA）	−14.57	−15.27	−11.86	−10.22
B点（IFA-PFA）	−24.36	−13.60	−21.16	−9.71
B点（PFA）	−13.23	−13.34	−9.89	−9.78
C点（IFA-PFA）	−24.84	−16.94	−22.61	−11.25
C点（PFA）	−13.22	−17.64	−9.89	−11.75

算法	IFA-PFA	PFA
平均用时	2.856 5	2.545 7

图片	二维信息熵/dB	SSIM （对比真实模板）
图16（b）	6.195 77	0.394453439
图16（e）	8.130 87	0.362239322

算法	真实点幅值	干扰点幅值（平均）
PFA	1601.02	1596.77
IFA-PFA	1519.71	35.8896

Low-altitude spotlight SAR fast imaging algorithm based on inter-pulse frequency agility

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