基于Keystone变换和扰动重采样的机动平台大斜视SAR成像方法

李根; 马彦恒; 侯建强; 徐公国

doi:10.11999/JEIT190831

基于Keystone变换和扰动重采样的机动平台大斜视SAR成像方法

doi: 10.11999/JEIT190831

1.
陆军工程大学石家庄校区无人机工程系石家庄 050003
2.
陆军工程大学石家庄校区电子与光学工程系石家庄 050003

详细信息

作者简介:
李根：男，1991年生，博士生，主要从事机动平台大斜视SAR成像和压缩感知雷达成像研究

马彦恒：男，1968年生，教授，博士生导师，主要从事机动SAR成像、低小慢目标探测等方向的研究

侯建强：男，1991年生，博士生，主要从事曲线SAR 3维成像研究

徐公国：男，1990年生，博士生，主要从事雷达信号处理与传感器融合研究

通讯作者:
李根　radarlg@163.com

中图分类号: TN957.52
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出版历程
- 收稿日期: 2019-10-28
- 修回日期: 2020-05-29
- 网络出版日期: 2020-06-04
- 刊出日期: 2020-10-13

Maneuvering Platform High-squint SAR Imaging Method Based on Keystone Transform and Perturbation Resampling

1.
Department of UAV Engineering, Army Engineering University Shijiazhuang Campus, Shijiazhuang 050003, China
2.
Department of Electronic and Optical Engineering, Army Engineering University Shijiazhuang Campus, Shijiazhuang 050003, China

摘要

摘要: 加速度和下降速度的存在使机动平台大斜视SAR的成像参数存在明显的2维空变性，严重影响场景的聚焦深度。针对这个问题，该文提出了一种基于Keystone变换和扰动重采样的机动SAR成像方法。首先，通过距离走动校正和去加速处理实现距离方位解耦以及方位频谱去混叠，然后采用方位时域的Keystone变换校正空变的距离徙动；在方位压缩过程中，通过引入时域的高阶扰动因子去除多普勒参数的2阶及3阶方位空变性，然后通过方位频域的重采样处理去除多普勒参数的方位1阶空变性。所提方法能够有效校正距离徙动轨迹和方位聚焦参数的2维空变性，实现机动平台大斜SAR的大场景成像，仿真分析验证了所提方法的有效性。
- SAR成像 /
- 大斜视 /
- 机动平台 /
- Keystone变换 /
- 扰动重采样
Abstract: The existence of acceleration and descent velocity makes the imaging parameters of high-squint SAR mounted on maneuvering platform have obvious two-dimensional spatial variability, which affects seriously the focus depth of the scene. To solve this problem, a maneuvering SAR imaging method based on Keystone transform and azimuth perturbation resampling is proposed. First of all, the range azimuth decoupling and the azimuth spectrum de Aliasing are realized by the range walk correction and de-acceleration processing. Then the spatial-variant range cell migration is corrected by the Keystone transform in the azimuth time domain; In the process of azimuth compression, the second- and third-order spatial variabilities of Doppler parameters are removed by introducing the high-order perturbation factor in the time domain, and then the first-order spatial variability of the Doppler parameters is removed by the azimuth resampling processing in the azimuth frequency domain. The proposed method can effectively correct the two-dimensional spatial variability of range cell migration trajectory and azimuth focus parameters, and realize the large scene imaging of high-squint maneuvering SAR. Simulation analysis verifies the effectiveness of the proposed method.
- SAR imaging /
- High-squint /
- Maneuvering platforms /
- Keystone transform /
- Perturbation resampling

HTML全文

图 1 机动平台大斜视SAR成像模型

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图 2 成像算法流程

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图 3 有效成像区域分析

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图 4 机动SAR成像目标分布示意图

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图 5 空变距离徙动校正结果

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图 6 点目标聚焦结果方位剖面图

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表 1 仿真参数

参数	数值	参数	数值
载频	15 GHz	地面斜视角	60°
距离带宽	300 MHz	平台高度	4 km
合成孔径时间	3 s	中心斜距	12 km
脉冲宽度	5 μs	速度	(150, 0, –30) m/s
脉冲重复频率	1.5 kHz	加速度	(2.4, 0.8, –2.2) m/s²

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表 2 点目标方位向测量指标

测量指标	FDPF方法^[13]			本文扰动重采样方法
测量指标	点1	点2	点3	点1	点2	点3
PSLR(dB)	–3.98	–13.26	–4.78	–12.68	–13.27	–13.39
ISLR(dB)	–7.11	–9.83	–6.78	–9.37	–9.81	–10.28
MW	20.67	15.60	28.35	15.62	15.61	15.62

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