低波段大波束角SAR 脉冲响应函数特性研究

对合成孔径雷达(SAR)而言,其成像性能的优劣或SAR 图像质量可通过成像系统的脉冲响应函数(IRF)来表征。脉冲响应函数可看作是一个理想点目标的成像结果,这一函数由中央主瓣和一些旁瓣组成。SAR 系统的图像质量可以通过描述IRF 的空间分辨率、峰值旁瓣比、积分旁瓣比等主要特征进行描述和评价。文中主要对工作于VHF/ UHF 频段的低频大波束角SAR 系统的脉冲响应函数(IRF鄄USAR)特性进行了研究,推导了超宽带大波束角条件下的脉冲响应函数。基于点目标的傅里叶支撑谱与脉冲响应函数之间的对应解析关系,分析了IRF鄄USAR 的响应特性,并基于仿真及实测数据对IRF-USAR 响应特性进行了验证。

A Study on Impulse Response Function for Low-frequency Wide-beam SAR

For synthetic aperture radar(SAR),the imaging results can be depicted by the impulse response function(IRF) of the imaging system. IRF can be viewed as the imaging result of an ideal point target. The resolution and side-lobe level can be analyzed by the IRF, and the performance of the imaging system can be further accomplished. In this paper, the IRF of the ultra-wide beam low-frequency SAR system is studied, which is different from the traditional narrow-band and narrow-beam SAR system. The precise IRF of the low-frequency ultra-wide beam SAR is deduced. Based on the relationship of the supported Fourier spectrum and the IRF, the characteristics of the IRF are analyzed and demonstrated by simulated and the real data.