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Analysis of High-Frequency EM Scattering Properties on Time-Varying Sea Surface

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Chinese Journal of Electronics 2016年第2期25卷 384-390页

作者： LI Changze tong chuangming QI Lihui WANG tong ZHAO Haizhou Air and Missile Defense College Air Force Engineering University Military Representative Office of PLA in 786 Factory

This paper proposes to solve the extralarge scale Electromagnetic(EM) scattering problem on a wind-driven sea surface at Low-grazing-angle(LGA) directed against a shore-based radar with an Iterative physical optics(IPO) model. Using Monte Carlo simulations,it compares the average Doppler spectra of backscattered signals at different angles and sea states. The methods are: the forward-backward methodology and its modification with under-relaxation iteration which improves convergence and stability of the IPO; the local iteration methodology and the Fast far-field approximation(Fa FFA)in the matrix-vector product which reduce the computational complexity based on the scattering characteristics of sea surface. The simulations show a broadening effect of the Doppler spectra in a more complicated sea state at LGA.

关键词： Shore-based radar Doppler spectra LGA Iterative model Forward-backward methodology

Iterative physical optics model for electromagnetic scattering and Doppler analysis

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Journal of Systems Engineering and Electronics 2016年第3期27卷 581-589页

作者： Changze Li chuangming tong Yan Bai Lihui Qi Air and Missile Defense College Air Force Engineering UniversityXi'an 710051China Military Representative Office of PLA in 786 Factory Xi'an 710051China

An iterative physical optics（IPO） model is proposed to solve extra large scale electric electromagnetic（EM） scattering from randomly rough surfaces. In order to accelerate the convergence of the IPO model, the forward-backward methodology and its modification with underrelaxation iteration are developed to simulate the rough surface scattering; the local iteration methodology and the fast far field approximation（Fa FFA） in the matrix-vector product are proposed to reduce greatly the computational complexity. These techniques make Monte Carlo simulations possible. Thus, the average Doppler spectra of backscattered signals obtained from the simulations are compared for different incident angles and sea states. In particular, the simulations show a broadening of the Doppler spectra for a more complicated sea state at a low grazing angle（LGA）.

关键词： electromagnetic(EM) scattering iterative physical optics(IPO) Doppler spectra high frequency surface wave radar(HFSWR)

New UWB imaging algorithm for multiple targets detection

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Journal of Systems Engineering and Electronics 2011年第6期22卷 905-909页

作者： Weijun Zhong chuangming tong Guorong Huang Yan Geng Missile Institute Air Force Engineering University Sanyuan 713800 R R. China State Key Laboratory of Millimeter Waves Nanjing 210096 E R. China Engineering Institute Air Force Engineering University Xi＇ an 710038 P. R. China Xi＇an Satellite Control Center Xi＇an 710043 E R China

Because the conventional ultra wideband（UWB） radar imaging algorithm cannot meet the demand in the capability of multiple targets detection,a novel UWB radar imaging algorithm based on the near field radiation theory of dipole is *** the foundation of researching the principle of a time domain imaging algorithm,the back projection（BP） algorithm is derived and ***,the far field sampling data are transferred to the near field sampling data by using the near field radiation theory of *** the BP algorithm is applied to target *** capability of the new algorithm to detect the multi-target is verified by using the finite-difference time-domain method,and the threedimensional images of targets are *** coupling effect between targets for imaging is *** simulation results show that the new UWB radar imaging algorithm based on the near field radiation theory of dipole could weaken the coupling effect for imaging,and as a result the quality of imaging is improved.

关键词： ultra wideband(UWB) back projection(BP) algorithm dipole finite-difference time-domain(FDTD) method.

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一维粗糙地表面下方埋藏目标SAR成像

计算物理 2012年第5期29卷 745-752页

作者：姬伟杰童创明空军工程大学导弹学院三原713800 毫米波国家重点实验室南京210096

提出一种快速实现一维粗糙地表面下方埋藏金属目标的成像算法.用层内波传播算法结合谱加速的前后向迭代算法(PILE+FB-SA)计算一维粗糙面下方埋藏金属目标的后向散射;用得到的后向散射数据结合后向投影算法实现二维SAR(synthetic apertur... 详细信息

提出一种快速实现一维粗糙地表面下方埋藏金属目标的成像算法.用层内波传播算法结合谱加速的前后向迭代算法(PILE+FB-SA)计算一维粗糙面下方埋藏金属目标的后向散射;用得到的后向散射数据结合后向投影算法实现二维SAR(synthetic aperture radar)成像,研究窗函数的选取,讨论目标位置及尺寸大小变化的影响.用具有高斯谱的粗糙面模拟实际地表面,并采用锥形波入射以减小人为截断粗糙面引起的边缘效应.由于散射数据由快速数值算法得到,该算法不受地面和目标参数限制,可以实现任意粗糙地表面和复杂目标成像,对地下目标探测具有重要的应用价值.

关键词： SAR成像地下埋藏目标探测粗糙地表面层内波传播算法

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复杂海面电磁散射的修正面元模型

西安交通大学学报 2017年第12期51卷 35-41页

作者：刘万萌童创明王童空军工程大学防空反导学院西安710051

针对合成孔径雷达成像系统中,利用传统面元模型在含泡沫的复杂海面环境下得到的面元后向散射场误差较大,导致成像模糊的问题,提出了一种复杂海面电磁散射的修正面元(MFM)模型。首先建立精确的海水介电模型来计算含泡沫海面介电常数;然... 详细信息

针对合成孔径雷达成像系统中,利用传统面元模型在含泡沫的复杂海面环境下得到的面元后向散射场误差较大,导致成像模糊的问题,提出了一种复杂海面电磁散射的修正面元(MFM)模型。首先建立精确的海水介电模型来计算含泡沫海面介电常数;然后基于Elfouhaily海谱模型生成具体的海面样本,并将其划分成一个个小面元;最后计算出各面元的散射场,将其叠加得到海面样本的散射结果。与实测数据的对比表明,传统面元模型在大入射角时的仿真结果出现衰减现象,而加入泡沫的修正面元模型将使衰减降低近10dB,增强了与实测数据的吻合度。采用MFM模型对海面电磁散射特性及布儒斯特效应进行实验,结果表明:风速对海面布儒斯特效应影响较大,在P波段当风速由4m/s增大至10m/s时,布儒斯特效应减弱85%左右。

关键词：修正面元模型海面电磁散射布儒斯特效应

A Modified Four Path Method for Calculating Coupling Field of Super-Low Altitude Aircraft Target

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Journal of Computer and Communications 2018年第12期6卷 64-73页

作者： Gaoxiang Zou chuangming tong Binglin Yu Hualong Sun Tao Song Air Force Engineering University Xi’an China The 95226 Army of the Chinese People’s Liberation Army Wuhan China

A novel modified four path method (FPM) is presented for calculating coupling field of super-low altitude aircraft target. Based on the hybrid method PO + MEC (Physical Optics and Method of Equivalent Currents), the antenna radiation pattern is introduced to consider the multipath interference from side lobe of seeker. The modified FPM is used to calculate the coupling field from super-low altitude aircraft target above different terrestrial environments. The curves of scattering coefficient are analyzed. The influences of height of target, root mean square (RMS), and incident angle on coupling field characteristics are discussed. The simulation results can be used for reference in detection for super-low altitude target and optimization for radar system.

关键词： Modified Four Path Method Antenna Radiation Pattern Super-Low Altitude Aircraft Target Coupling Field Brewster Angle

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基于近场散射模型的超低空目标雷达回波模拟

系统工程与电子技术 2022年第1期44卷 139-145页

作者：王童童创明王宜进刘杰空军工程大学防空反导学院陕西西安710051 中国人民解放军94782部队浙江杭州310021

近区超低空目标具有更为复杂的电磁散射机理,需要建立更为精细灵活的回波模型。基于改进的物理光学与等效电磁流方法建立了目标的近场散射模型,结合面元模型与"四路径"模型提出环境与多径的近区散射计算方法。利用建立的电磁模型,以雷... 详细信息

近区超低空目标具有更为复杂的电磁散射机理,需要建立更为精细灵活的回波模型。基于改进的物理光学与等效电磁流方法建立了目标的近场散射模型,结合面元模型与"四路径"模型提出环境与多径的近区散射计算方法。利用建立的电磁模型,以雷达导引头探测近区超低空目标为应用背景,建立了雷达回波信号模型。验证了近场电磁模型的有效性,仿真分析了信号带宽以及雷达与目标不同相对运动状态对回波信号的影响。仿真结果表明,回波模型较好地表现了复杂场景的各种散射机理,对于探索近区超低空目标回波的特征与规律具有理论意义与实用价值。

关键词：超低空近场散射模型雷达回波

A New Algorithm of Tracking Ballistic Missiles

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A New Algorithm of Tracking Ballistic Missiles

地海交界分区域复合粗糙面建模及电磁散射特性研究

2013教育技术与信息系统国际会议

作者： Lifeng Qi Guanglong Jiao chuangming tong School of Air and Missile Defense of Air Force Engineering University

A new algorithm for the problem of initiating the tracks assuming the target trajectories follow a deterministic state propagation, through the maximum likelihood (ML) estimator combined with the probabilistic data association (PDA) First some well-known approaches for statistical model selection and the advantage of using the MDL criterion were reviewed, Then a one-dimensional example was used to illustrate the MDL criterion for multiple composite hypothesis testing and the performance limit of the ML-PDA for track initiation interpreted in terms of the sharpness of the hypothesis testing. Finally, The MDL approach for the detection and initiation of tracks of incoming tactical ballistic missiles in the exo-atmospheric phase was applied using a surface based electronically scanned array (ESA) radar. The targets were characterized by low SNR, which lead to low detection probability and high false alarm rate. A batch of radar scans were processed to detect the presence of up to two targets. The ML-PDA estimator was used to initiate the tracks assuming the target trajectories follow a deterministic state propagation.

关键词： Ballistic issiles Target tracking Maximum likelihood estimator(ML) Probabilistic data association (PDA)

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系统工程与电子技术 2017年第7期39卷 1425-1438页

作者：邹高翔童创明王童孙华龙空军工程大学防空反导学院陕西西安710051 东南大学毫米波国家重点实验室江苏南京210096

研究了地海交界分区域复合粗糙面的建模方法及其电磁散射特性。采用蒙特卡罗方法建立地海交界分区域复合粗糙面模型,采用高斯谱模拟实际地面,采用变浅系数与北海联合海浪计划(joint north sea wave project,JONSWAP)谱结合而成的有限水... 详细信息

研究了地海交界分区域复合粗糙面的建模方法及其电磁散射特性。采用蒙特卡罗方法建立地海交界分区域复合粗糙面模型,采用高斯谱模拟实际地面,采用变浅系数与北海联合海浪计划(joint north sea wave project,JONSWAP)谱结合而成的有限水深海谱模拟实际近海海面,基于分区域复合粗糙面建模理论,运用多种加权反正切函数处理实现了线型、月牙型、峡谷型自然环境。考虑了各介质区域内部的面元耦合以及区域之间和交界处面元的耦合作用,对地海交界分区域复合粗糙面的散射问题,提出了一种基于分区域面元的迭代物理光学法,采用快速远场近似(fast far field approximation,FaFFA)与局部耦合技术加速其迭代过程。对比了陆地粗糙面、海面和地海交界分区域复合粗糙面的电磁散射特性,计算了分区域复合粗糙面的散射系数,并讨论了极化方式、入射角、边界形状、陆地粗糙面的均方根高度、相关长度和近海海面的风速对地海交界分区域复合粗糙面电磁散射特性的影响。基于迭代物理光学法所获取的分区域复合粗糙面总散射场,采用正侧视条带式成像模式,选用距离多普勒算法对不同特点的地海分区域复合粗糙面进行合成孔径雷达(synthetic aperture radar,SAR)成像,并讨论了陆地粗糙面与海面各自的相对介电常数对SAR成像的影响。该研究包括了地海交界环境的建模、电磁散射特性的求解及其SAR成像,由仿真结果得到了地海交界分区域复合粗糙面的SAR像特点,对反演地海交界环境的电磁特性以及遥感、探测具有借鉴意义。

关键词：地海交界近海海面分区域复合粗糙面迭代物理光学法合成孔径雷达成像