一种结合稀疏重建和匹配滤波的距离模糊抑制方法

Method of Range Ambiguity Suppression Combining Sparse Reconstruction and Matched Filtering

由于SAR天线旁瓣特性和脉冲工作体制,SAR图像在一定程度上受到距离模糊的影响。距离模糊抑制工作分别聚焦在SAR系统设计和SAR信号处理两个方面。前者通过天线赋形、正交编码等方式减小距离模糊能量接收,后者利用信号处理技术在回波域和图像域消除距离模糊能量。该文提出了一种结合稀疏重建和匹配滤波技术的距离模糊抑制方法。该方法对模糊区进行稀疏重建,利用模糊区图像和重建矩阵估计模糊区信号,从回波信号中将其分离得到模糊抑制后的主像信号,后续利用匹配滤波技术获得主像图像。该方法利用稀疏重建技术保证了模糊区信号估计的精度,利用匹配滤波技术保证了成像处理的效率。仿真实验表明,该方法可以有效抑制距离模糊,抑制效果可达10 dB及以上,并且对主像弱目标和细节具有很好的保持能力。

To a certain extent,SAR images are affected by range ambiguity due to antenna sidelobe characteristics and pulse operating system.The work of range ambiguity suppression focuses on SAR system design and signal processing.One type of idea tries to modify the way of transmitting and receiving to block the receiving of the ambiguous energy,such as multiple elevation beams and azimuth phase coding.The other ideas are algorithms that use signal processing technology to reduce the distance ambiguity energy in echo and image domains.This paper proposes a range ambiguity suppression method that combines sparse reconstruction and matched filtering.The method performs the sparse reconstruction of the ambiguity area,estimates the ambiguity area signal using the ambiguity area image and reconstruction matrix,separates it from the echo signal to obtain the primary image signal after range ambiguity suppression,and uses matched filtering to obtain the main area image.In this method,sparse reconstruction ensures the accuracy of fuzzy signal estimation,and matched filtering ensures the efficiency of imaging processing.Simulation results show that the proposed method can effectively suppress range ambiguity,with a suppression effect of 10 dB or higher,and it has a good ability to maintain the weak targets and the details of the main image.