基于加速度斜距模型的大场景超高分辨率星载SAR成像方法
doi: 10.11999/JEIT140928
An Imaging Algorithm for Wide-field and Super High-resolution Spaceborne SAR Based on Acceleration Slant Range Model
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摘要: 在大场景超高分辨率星载合成孔径雷达(SAR)中，等效速度在方位向上的空变性会导致方位散焦，此时传统的双曲线斜距模型已经不再适用，针对这个问题，该文提出一种新的加速度斜距模型，该模型可以把速度的方位空变特性考虑在内。在此模型的基础上，该文还给出了相应的信号处理和成像方法，首先通过方位时域重采样消除速度的方位空变性，然后在2维频域去除三次项和四次项误差，最后再采用距离徙动算法(RMA)进行成像。仿真实验的结果证明了新的加速度斜距模型和成像方法的有效性。Abstract: In the wide-field and super high-resolution spaceborne Synthetic Aperture Radar (SAR), the traditional hyperbolic slant range model is no longer available, which is due to the variance of equivalent velocity in azimuth direction is able to cause azimuth defocus. For this problem, this paper proposes a new acceleration slant range model, which considers the azimuth variance of equivalent velocity. Based on this model, the corresponding signal processing and imaging method is given. Firstly, the azimuth variance of velocity is eliminated by azimuth resampling in the time domain. Secondly, the third-order and fourth-order error is eliminated in the 2D frequency domain. Finally, Range Migration Algorithm (RMA) is used to get the final image. The simulation results validate the effectiveness of the new acceleration slant range model and imaging algorithm.
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