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首页> 外文会议>Algorithms for Synthetic Aperture Radar Imagery XXIII >Performance of Several Imaging Methodologies in Extraction of Secondary SAR Slow-Time Signals
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Performance of Several Imaging Methodologies in Extraction of Secondary SAR Slow-Time Signals

机译：几种成像方法在次级SAR慢信号提取中的性能

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摘要

In Synthetic Aperture Radar (SAR) the resultant image gives not only the complex reflectivity of image points but also their interdependency with respect to time and observation angle. In range or fast-time changes in reflectivity are expectedly slight, however, in observation azimuth or slow-time the reflectivity pattern, movement or vibration of strong scatterers is revealed. These azimuth signals can subequently reveal pass to pass changes over inter-pass time or observation elevation. Key to extracting the slow-time signals is the imaging method involved. If imaging preserves the phase function across azimuth then the time or aspect phenomenon riding on top of the phase can be extracted. In other cases the phase is distorted or overridden by imaging artifacts. The choice of imaging method is fundamental in determining not only image resolution but also the fidelity with which secondary signals along the aperture can be determined. The achievable envelope of secondary signal amplitude, bandwidth and resolution are determined here for several imaging methods including the fraction Fourier transform, deramping, range-doppler, chirp scaling, wave-front and matched filtering. Method of extracting these secondary azimuth dependent signals are developed and results are presented for an orbital scenario. Naturally sampling speed, pulse spacing and the flight path in slow-time enclose the largest potential envelope of measurable secondary signals while the selection of imaging method restricts the potential measurable signals to a smaller envelope. Sampling restrictions and bounds on range migration curvature for different imaging methods are also found.
机译：在合成孔径雷达（SAR）中，所得图像不仅给出了像点的复杂反射率，而且还给出了它们在时间和观察角度方面的相互依赖性。反射率的范围或快速变化预计是微小的，但是，在观察方位角或慢时，反射率模式，强散射体的移动或振动会显示出来。这些方位角信号可以随后显示通过时间或观察高度上的通过变化。提取慢时间信号的关键是所涉及的成像方法。如果成像保留了跨方位角的相位功能，则可以提取出相位顶部的时间或纵横比现象。在其他情况下，相位会因成像伪影而失真或被覆盖。成像方法的选择不仅是确定图像分辨率的基础，而且是确定沿孔径的二次信号的保真度的基础。此处针对几种成像方法确定了次级信号幅度，带宽和分辨率可达到的包络，包括分数傅里叶变换，解斜坡，距离多普勒，线性调频缩放，波前和匹配滤波。开发了提取这些次要方位角相关信号的方法，并给出了针对轨道情景的结果。自然的采样速度，脉冲间隔和慢速飞行路径会包围可测量的次级信号的最大潜在包络，而成像方法的选择会将潜在的可测量信号限制在较小的包络中。还发现了不同成像方法对距离偏移曲率的采样限制和边界。

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