地面运动目标速度较大时,会产生距离徙动,在图像域出现严重散焦,不易检测;同时存在PRF模糊现象,其多普勒频谱会发生折叠,不易正确定位。针对上述问题,提出了基于机载三通道SAR-GMTI的地面快速目标检测、定位与成像方法。首先,在距离压...地面运动目标速度较大时,会产生距离徙动,在图像域出现严重散焦,不易检测;同时存在PRF模糊现象,其多普勒频谱会发生折叠,不易正确定位。针对上述问题,提出了基于机载三通道SAR-GMTI的地面快速目标检测、定位与成像方法。首先,在距离压缩后的数据域进行相位中心偏置天线(displaced phase center anten-na,DPCA)杂波抑制,组合运用Canny算子、Ratio算子和Hough变换提取快速目标运动轨迹。然后,采用基于解PRF后的二阶Keystone变换方法完成目标的成像、检测及运动参数估计。最后,将快速目标融合到标有慢速运动目标的清晰SAR图像中。外场实测结果验证了该方法的有效性和准确性。展开更多
天线相位中心偏置(DPCA,Displaced Phase Center Antenna)技术应用于双通道SAR图像域检测地面慢动目标,具有操作简单、高效实用的特点,因此寻找性能更优的DPCA检测量具有重要的理论和实际意义。本文在深入分析经典图像域DPCA检测量存在...天线相位中心偏置(DPCA,Displaced Phase Center Antenna)技术应用于双通道SAR图像域检测地面慢动目标,具有操作简单、高效实用的特点,因此寻找性能更优的DPCA检测量具有重要的理论和实际意义。本文在深入分析经典图像域DPCA检测量存在的不足的基础上,引入多视平均、共轭相乘处理,提出了几种新的DPCA检测量。理论分析和实验验证表明:新DPCA检测量具有杂波和噪声抑制能力强、旁瓣抑制好、定位精度高等特点,说明共轭相乘操作和多视平均处理能够有效地弥补经典DPCA检测量的缺陷,有效提高检测性能。此外,理论推导了随机噪声和通道之间的绝对增益误差等干扰因素对DPCA检测量的影响,证明了新DPCA检测量具有较强的抗干扰性。展开更多
Synthetic aperture radar （SAR） systems have become an important tool for fine-resolution mapping and other remote sensing operations. The multi-channel SAR ground moving-target indication （GMTI） must process its d...Synthetic aperture radar （SAR） systems have become an important tool for fine-resolution mapping and other remote sensing operations. The multi-channel SAR ground moving-target indication （GMTI） must process its data to produce not only the image of surveillance area but also the information of the ground moving-targets. The topic of moving-target detection in clutter has been extensively studied, and there are many methods that are used to detect moving targets, such as displaced phase center antenna （DPCA） method, along-track interfero-metric （ATI） phase, space-time adaptive processing （STAP）, or some other metrics. A canonical framework is proposed that encompasses all the multi-channel SAR-GMT methods, namely, DPCA and ATI. The statistical test metric for multi-channel SAR-GMTI is established in a simple form, via the definition of the complex central Wishart distribution, to deduce the statistics of the test metric, and the probability distribution of the test metric for multichannel SAR-GMTI has the complex central Wishart distribution of 1×1 case, namely the X^2 distribution. The theory foundation offers the possibility to construct the united multi-channel SAR-GMTI detector, and derives the constant false alarm rate （CFAR） detector tests for separating moving targets from clutter.展开更多
文摘地面运动目标速度较大时,会产生距离徙动,在图像域出现严重散焦,不易检测;同时存在PRF模糊现象,其多普勒频谱会发生折叠,不易正确定位。针对上述问题,提出了基于机载三通道SAR-GMTI的地面快速目标检测、定位与成像方法。首先,在距离压缩后的数据域进行相位中心偏置天线(displaced phase center anten-na,DPCA)杂波抑制,组合运用Canny算子、Ratio算子和Hough变换提取快速目标运动轨迹。然后,采用基于解PRF后的二阶Keystone变换方法完成目标的成像、检测及运动参数估计。最后,将快速目标融合到标有慢速运动目标的清晰SAR图像中。外场实测结果验证了该方法的有效性和准确性。
文摘天线相位中心偏置(DPCA,Displaced Phase Center Antenna)技术应用于双通道SAR图像域检测地面慢动目标,具有操作简单、高效实用的特点,因此寻找性能更优的DPCA检测量具有重要的理论和实际意义。本文在深入分析经典图像域DPCA检测量存在的不足的基础上,引入多视平均、共轭相乘处理,提出了几种新的DPCA检测量。理论分析和实验验证表明:新DPCA检测量具有杂波和噪声抑制能力强、旁瓣抑制好、定位精度高等特点,说明共轭相乘操作和多视平均处理能够有效地弥补经典DPCA检测量的缺陷,有效提高检测性能。此外,理论推导了随机噪声和通道之间的绝对增益误差等干扰因素对DPCA检测量的影响,证明了新DPCA检测量具有较强的抗干扰性。
基金the National Natural Science Foundation of China (60472097 and 60502054)
文摘Synthetic aperture radar （SAR） systems have become an important tool for fine-resolution mapping and other remote sensing operations. The multi-channel SAR ground moving-target indication （GMTI） must process its data to produce not only the image of surveillance area but also the information of the ground moving-targets. The topic of moving-target detection in clutter has been extensively studied, and there are many methods that are used to detect moving targets, such as displaced phase center antenna （DPCA） method, along-track interfero-metric （ATI） phase, space-time adaptive processing （STAP）, or some other metrics. A canonical framework is proposed that encompasses all the multi-channel SAR-GMT methods, namely, DPCA and ATI. The statistical test metric for multi-channel SAR-GMTI is established in a simple form, via the definition of the complex central Wishart distribution, to deduce the statistics of the test metric, and the probability distribution of the test metric for multichannel SAR-GMTI has the complex central Wishart distribution of 1×1 case, namely the X^2 distribution. The theory foundation offers the possibility to construct the united multi-channel SAR-GMTI detector, and derives the constant false alarm rate （CFAR） detector tests for separating moving targets from clutter.
