摘要
分布式星载SAR利用不同视角回波信号之间地面散射频谱不同的特性来提高SAR图像的距离向分辨率 .其数据处理的关键就是如何将这些不同频段的信号相结合 ,得到具有更宽频谱的高分辨率图像 .本文提出了一种基于频谱偏移估计的分布式星载SAR提高距离向SAR图像分辨率的数据处理方法 .该方法的主要思想是在SAR复图像的基础上 ,通过精确的估计 ,得到SAR复图像间的距离向频谱偏移量 ,并根据该偏移量 ,在频域进行距离向频谱偏移补偿后将图像相加 .建立了分布式星载SAR单视复图像的信号模型 ,推导了基于频谱偏移估计提高SAR图像距离向分辨率的原理公式 ,给出了基于频谱偏移估计提高距离向分辨率的具体数据处理步骤 .最后采用仿真数据验证了理论推导的正确性和数据处理方法的有效性 .
Distributed spaceborne SAR can produce SAR images with different scattering spectrum.The combination of these SAR images was used to improve the range resolution in final image product.The key point in its data processing was how to correctly join these different spectrums to a wider range spectrum.A new algorithm based on spectrum shift estimation for improving range resolution was proposed to process distributed spaceborne SAR data.The algorithm firstly estimated the spectrum shift between SAR complex images acquired by small satellites.Then the spectrum shift was compensated to these complex images in frequency field.Finally the compensated SAR images were added to form final image with improved range resolution.According to SAR complex image model,the new algorithm was derived.The steps to implement the algorithm mainly included image registration,spectrum shift estimation,spectrum shift compensation and image addition and every step was presented in detail.FFT were used in the algorithm to reduce its processing time.In last,computer simulation was employed to test the new algorithm.
出处
《电子学报》
EI
CAS
CSCD
北大核心
2003年第12期1790-1794,共5页
Acta Electronica Sinica
