提出联合Zernike矩、核主成分分析(kernel principal component analysis,KPCA)及单演信号特征的合成孔径雷达(synthetic aperture radar,SAR)目标识别方法,3类特征分别描述SAR目标几何形状特征、投影特征及图像分解特征,联合使用可以...提出联合Zernike矩、核主成分分析(kernel principal component analysis,KPCA)及单演信号特征的合成孔径雷达(synthetic aperture radar,SAR)目标识别方法,3类特征分别描述SAR目标几何形状特征、投影特征及图像分解特征,联合使用可以有效增强对目标的描述。分类阶段采用联合稀疏表示对测试样本的3类特征进行表征。对于3类特征的输出误差矢量,采用多组权值矢量进行加权融合,进而根据最终融合的误差判定测试样本的目标类别。基于MSTAR(moving and stationary target acquisition and recognition)数据集的标准操作条件、扩展操作条件及少量训练样本条件对所提方法进行测试,结果验证了所提方法的有效性、稳健性及对少量训练样本的适应性。展开更多
基于典型地面背景电磁散射特性的研究,提出了介质粗糙地面上目标散射中心正向建模的方法。首先,通过蒙特卡罗方法随机生成粗糙面,利用高斯谱模拟三维粗糙地面模型,采用介电常数对不同地面材料进行表征;然后,采用正向途径并结合射线追踪...基于典型地面背景电磁散射特性的研究,提出了介质粗糙地面上目标散射中心正向建模的方法。首先,通过蒙特卡罗方法随机生成粗糙面,利用高斯谱模拟三维粗糙地面模型,采用介电常数对不同地面材料进行表征;然后,采用正向途径并结合射线追踪、分集技术将复杂的地面环境与MSTAR(Moving and Stationary Target Acquisition and Recognition)库中的BMP2步兵战车目标模型的整体散射离散为多个散射源的集合,再结合粗糙地面的不同介电常数进行分析,利用高频近似方法进行求解;最后,通过重构的合成孔径雷达(synthetic aperture radar,SAR)图像与MSTAR库实测数据集对比进行验证。结果表明,本文提出的介质粗糙地面上目标散射中心正向建模方法能够提高与实测图像数据的相似度,验证了其有效性。展开更多
Separated transmit and receive antennas are employed to improve transmit-receive isolation in conventional short-range radars, which greatly increases the antenna size and misaligns of the transmit/receive radiation p...Separated transmit and receive antennas are employed to improve transmit-receive isolation in conventional short-range radars, which greatly increases the antenna size and misaligns of the transmit/receive radiation patterns. In this paper,a dual circularly polarized(CP) monostatic simultaneous transmit and receive(MSTAR) antenna with enhanced isolation is proposed to alleviate the problem. The proposed antenna consists of one sequentially rotating array(SRA), two beamforming networks(BFN), and a combined decoupling structure. The SRA is shared by the transmit and receive to reduce the size of the antenna and to obtain a consistent transmit and receive pattern.The BFN achieve right-hand CP for transmit and left-hand CP for receive. By exploring the combined decoupling structure of uniplanar compact electromagnetic band gap(UC-EBG) and ringshaped defected ground structure(RS-DGS), good transmitreceive isolation is achieved. The proposed antenna prototype is fabricated and experimentally characterized. The simulated and measured results show good agreement. The demonstrate transmit/receive isolation is height than 33 dB, voltage standing wave ratio is lower than 2, axial ratio is lower than 3 dB, and consistent radiation for both transmit and receive is within4.25-4.35 GHz.展开更多
文摘提出联合Zernike矩、核主成分分析(kernel principal component analysis,KPCA)及单演信号特征的合成孔径雷达(synthetic aperture radar,SAR)目标识别方法,3类特征分别描述SAR目标几何形状特征、投影特征及图像分解特征,联合使用可以有效增强对目标的描述。分类阶段采用联合稀疏表示对测试样本的3类特征进行表征。对于3类特征的输出误差矢量,采用多组权值矢量进行加权融合,进而根据最终融合的误差判定测试样本的目标类别。基于MSTAR(moving and stationary target acquisition and recognition)数据集的标准操作条件、扩展操作条件及少量训练样本条件对所提方法进行测试,结果验证了所提方法的有效性、稳健性及对少量训练样本的适应性。
文摘基于典型地面背景电磁散射特性的研究,提出了介质粗糙地面上目标散射中心正向建模的方法。首先,通过蒙特卡罗方法随机生成粗糙面,利用高斯谱模拟三维粗糙地面模型,采用介电常数对不同地面材料进行表征;然后,采用正向途径并结合射线追踪、分集技术将复杂的地面环境与MSTAR(Moving and Stationary Target Acquisition and Recognition)库中的BMP2步兵战车目标模型的整体散射离散为多个散射源的集合,再结合粗糙地面的不同介电常数进行分析,利用高频近似方法进行求解;最后,通过重构的合成孔径雷达(synthetic aperture radar,SAR)图像与MSTAR库实测数据集对比进行验证。结果表明,本文提出的介质粗糙地面上目标散射中心正向建模方法能够提高与实测图像数据的相似度,验证了其有效性。
基金supported by Guangdong Natural Science Foundation(2019A1515011622)Guangdong Provincial Laboratory of Southern Marine Science and Engineering (Zhuhai)(SML2021SP407)。
文摘Separated transmit and receive antennas are employed to improve transmit-receive isolation in conventional short-range radars, which greatly increases the antenna size and misaligns of the transmit/receive radiation patterns. In this paper,a dual circularly polarized(CP) monostatic simultaneous transmit and receive(MSTAR) antenna with enhanced isolation is proposed to alleviate the problem. The proposed antenna consists of one sequentially rotating array(SRA), two beamforming networks(BFN), and a combined decoupling structure. The SRA is shared by the transmit and receive to reduce the size of the antenna and to obtain a consistent transmit and receive pattern.The BFN achieve right-hand CP for transmit and left-hand CP for receive. By exploring the combined decoupling structure of uniplanar compact electromagnetic band gap(UC-EBG) and ringshaped defected ground structure(RS-DGS), good transmitreceive isolation is achieved. The proposed antenna prototype is fabricated and experimentally characterized. The simulated and measured results show good agreement. The demonstrate transmit/receive isolation is height than 33 dB, voltage standing wave ratio is lower than 2, axial ratio is lower than 3 dB, and consistent radiation for both transmit and receive is within4.25-4.35 GHz.
