联合等效斜距模型和自聚焦的地面动目标成像

doi:10.7527/S1000-6893.2024.30559

Abstract

Abstract:

A refocusing algorithm for post-processing defocused images is proposed to address the problem of defocusing in Synthetic Aperture Radar （SAR） imaging results caused by translational motion of the target. Firstly， in response to the problem that the spatial variation of the Taylor expansion coefficient of the target’s slant range spatially with the target’s azimuth will result in the loss of azimuth invariance， an equivalent slant range model with non spatially varying coefficients is proposed. This slant range model can weaken the phase error caused by time domain range walk correction in squint imaging. Secondly， to address the mismatch of frequency domain compensation function caused by Doppler ambiguity and the different residual phase forms in different SAR algorithm results， the frequency domain truncation and inverse matching methods are used to obtain the equivalent echo data after Doppler center correction. Finally， the residual phase is estimated and compensated using the minimum entropy autofocus method， resulting in a focused image. The effectiveness of the proposed algorithm is verified through simulation experiments.

Key words: synthetic aperture radar (SAR), ground moving target imaging (GMTIm), refocus, slant range model, autofocus

CLC Number:

V243.2

Li YAN, Jie ZHANG, Jiadong WANG. [J]. Acta Aeronautica et Astronautica Sinica, 2024, 45(S1): 730559.

Figures/Tables 18

Fig.1

Fig.2

Fig.3

Fig.4

Table 1

Radar parameters

参数	数值	参数	数值
载频 $f c$ /GHz	10	积累时间 $T a$ /s	1.93
作用距离 $R s$ /Km	10	斜视角 $θ 0$ /（°）	75
信号脉宽 $T p$ / us	2	重频PRF/Hz	530
信号带宽 $B r$ /MHz	210	平台速度 $v$ /（m·s ^-1）	150

Table 1

Table 2

Target motion parameters

目标	$v x$ /（m·s ^-1）	$v z$ /（m·s ^-1）
1	-10	7
2	5	10
4	9	7

Table 2

Fig.5

Fig.6

Fig. 7

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Fig.9

Table 3

Performance of different scattering points on Target 1

目标	P积分旁瓣比/dB（距离向/方位向）			峰值旁瓣比/dB（距离向/方位向）
目标	RD	RID	所提算法	RD	RID	所提算法
$P 1$	-0.65/-8.90	-34.38/-13.00	-13.17/-13.24	1.06/-9.13	-30.52/-10.15	-10.77/-10.72
$P 2$	-1.20/-13.15	-23.57/-12.66	-13.21/-13.52	0.86/-12.03	-12.66/-9.86	-10.71/-10.85
$P 3$	-1.13/-10.87	-29.66/-13.03	-13.05/-13.03	0.65/-8.03	-13.03/-9.66	-10.54/-10.55

Table 3

Fig.10

Fig. 11

Fig.12

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References 21

1	SONG X， LI Y C， ZHANG T H， et al. Focusing high-maneuverability bistatic forward-looking SAR using extended azimuth nonlinear chirp scaling algorithm［J］. IEEE Transactions on Geoscience and Remote Sensing， 2022， 60： 5240814.
2	李亚超，王家东，张廷豪，等. 弹载雷达成像技术发展现状与趋势［J］. 雷达学报， 2022， 11（ 6）： 943- 973.
	LI Y C， WANG J D， ZHANG T H， et al. Present situation and prospect of missile-borne radar imaging technology［J］. Journal of Radars， 2022， 11（ 6）： 943- 973 （in Chinese）.
3	ZHANG T H， LI Y C， WANG J， et al. A modified range model and extended omega-K algorithm for high-speed-high-squint SAR with curved trajectory［J］. IEEE Transactions on Geoscience and Remote Sensing， 2023， 61： 5204515.
4	保铮，邢孟道，王彤. 雷达成像技术［M］. 北京：电子工业出版社， 2005.
	BAO Z， XING M D， WANG T. Radar imaging technology［M］. Beijing： Publishing House of Electronics Industry， 2005 （in Chinese）.
5	余涛. 改进高机动平台曲线轨迹SAR频域成像算法研究［D］. 西安：西安电子科技大学， 2019.
	YU T. Research on improved frequency domain imaging algorithm of curved trajectory SAR for high maneuvering platform［D］. Xi’an： Xidian University， 2019 （in Chinese）.
6	CAO R， WANG Y， ZHAO B， et al. Ship target imaging in airborne SAR system based on automatic image segmentation and ISAR technique［J］. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing， 2021， 14： 1985- 2000.
7	LI Z Y， ZHANG X D， YANG Q， et al. Hybrid SAR-ISAR image formation via joint FrFT-WVD processing for BFSAR ship target high-resolution imaging［J］. IEEE Transactions on Geoscience and Remote Sensing， 2021， 60： 5215713.
8	XU X B， SU F L， GAO J J， et al. High-squint SAR imaging of maritime ship targets［J］. IEEE Transactions on Geoscience and Remote Sensing， 1864， 60： 5200716.
9	LI R A， YAN H， WU C， et al. Low-flying moving target detection and imaging algorithm of spaceborne SAR based on two-dimensional velocity search［C］∥ 2022 14th International Conference on Signal Processing Systems （ICSPS）. Piscataway： IEEE Press， 2022： 437- 443.
10	SAHAY P， JAIN A， RADHAKRISHNA P， et al. Parameter estimation and imaging of SAR ground moving target using AGFS［C］∥ 2021 IEEE International Conference on Electronics， Computing and Communication Technologies （CONECCT）. Piscataway： IEEE Press， 2021： 1- 6.
11	YANG J F， ZHANG Y H. Squint SAR ground moving target imaging and motion parameters estimation with keystone transform［C］∥ 2018 Asia-Pacific Microwave Conference （APMC）. Piscataway： IEEE Press， 2018： 827- 829.
12	GU D D， YUE H， LU B T， et al. Velocity estimation for moving target refocusing in the long-time coherent integration SAR imaging［C］∥ 2018 China International SAR Symposium （CISS）. Piscataway： IEEE Press， 2018： 1- 4.
13	熊世超，倪嘉成，张群，等. 基于频谱旋转ωk算法的大斜视SAR地面动目标成像［J］. 系统工程与电子技术， 2022， 44（ 10）： 3104- 3114.
	XIONG S C， NI J C， ZHANG Q， et al. High-squint mode SAR GMTIm based on ωk algorithm with spectrum rotation［J］. Systems Engineering and Electronics， 2022， 44（ 10）： 3104- 3114 （in Chinese）.
14	HAN J S， CAO Y H， YEO T S， et al. Robust clutter suppression and ground moving target imaging method for a multichannel SAR with high-squint angle mounted on hypersonic vehicle［J］. Remote Sensing， 2021， 13（ 11）： 2051.
15	WANG Y， JIANG Y C. ISAR imaging for three-dimensional rotation targets based on adaptive Chirplet decomposition［J］. Multidimensional Systems and Signal Processing， 2010， 21（ 1）： 59- 71.
16	LI J， LING H. Application of adaptive chirplet representation for ISAR feature extraction from targets with rotating parts［J］. IEE Proceedings-Radar， Sonar and Navigation， 2003， 150（ 4）： 284.
17	DU Y H， JIANG Y C， WANG Y， et al. ISAR imaging for low-earth-orbit target based on coherent integrated smoothed generalized cubic phase function［J］. IEEE Transactions on Geoscience and Remote Sensing， 2020， 58（ 2）： 1205- 1220.
18	HUANG P H， XIA X G， ZHAN M Y， et al. ISAR imaging of a maneuvering target based on parameter estimation of multicomponent cubic phase signals［J］. IEEE Transactions on Geoscience and Remote Sensing， 2021， 60： 5103918.
19	LI Y C， WANG J D， WANG Y， et al. Random-frequency-coded waveform optimization and signal coherent accumulation against compound deception jamming［J］. IEEE Transactions on Aerospace and Electronic Systems， 2023， 59（ 4）： 4434- 4449.
20	ZHANG L， SHENG J L， DUAN J， et al. Translational motion compensation for ISAR imaging under low SNR by minimum entropy［J］. EURASIP Journal on Advances in Signal Processing， 2013， 2013： 33.
21	CHEN V C， MARTORELLA M. Inverse synthetic aperture radar imaging： principles， algorithms and applications［M］. IET， 2014.

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[2]	Penghui JI, Shiqi XING, Dahai DAI, Bo Pang, Dejun FENG. A SAR scene deceptive jamming method based on range convolution and azimuth multiplication modulation [J]. Acta Aeronautica et Astronautica Sinica, 2023, 44(18): 328235-328235.
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[4]	LU Jingyue, ZHANG Lei, MENG Zhichao, SHENG Jialian. Unambiguous imaging for forward-looking synthetic aperture radar on curve trajectory [J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2019, 40(7): 322745-322745.
[5]	ZHU Xiaoxiu, HU Wenhua, MA Juntao, GUO Baofeng, XUE Dongfang. ISAR autofocusing imaging with sparse apertures and time-varying bistatic angle [J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2018, 39(8): 322059-322059.
[6]	HAN Ning, LI Baochen, WANG Libing, TONG Jun, GUO Baofeng. Algorithm for autofocusing of bistatic ISAR of space target based on sparse decomposition [J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2018, 39(8): 322037-322037.
[7]	YANG Mingdong, YU Xiang, ZHU Daiyin. High-precision space-variant motion compensation with multi-level processing for airborne SAR based on subswath [J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2018, 39(2): 321557-321557.
[8]	ZHOU Longjian, LUO Jingqing, YU Zhifu, WU Shilong. A multi-pulse passive localization algorithm for bistatic moving stations [J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2017, 38(2): 320251-320260.
[9]	WEI Beiyu, ZHU Daiyin, WU Di. Multichannel SAR-GMTI based on clutter cancellation and autofocus [J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2015, 36(5): 1585-1595.
[10]	WANG Xin, ZHU Daiyin, JIANG Rui. Autofocus Method of Airborne SAR Imagery Reconstructed via Backprojection [J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2014, 35(11): 3074-3081.
[11]	MAO Xinhua, ZHU Daiyin, ZHU Zhaoda. 2-D Autofocus Algorithm for Ultra-high Resolution Airborne Spotlight SAR Imaging [J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2012, 33(7): 1289-1295.
[12]	HAN Ning, WANG Libing, HE Qiang, DONG Jian. BISAR Autofocusing Algorithm of Space Targets in Presence of Bistatic Angle Changes [J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2012, 33(10): 1864-1871.
[13]	Jiang Rui;Zhu Daiyin;Zhu Zhaoda. A Novel Approach to Strip-map SAR Autofocus [J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2010, 31(12): 2385-2392.
[14]	ZHU Dai-yin;ZHU Zhao-da. Study on Patch Mapping by Azimuth Scan SAR [J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2005, 26(2): 208-213.
[15]	Zhong Rui;Mao Shi-yi. A Modified PGA ML Phase Estimation Method [J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2003, 24(6): 537-540.

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