基于二维指数脉冲压缩变换的SAR成像算法

A new SAR imaging algorithm based on two-dimensional exponential pulse compression transform

摘要:

传统的合成孔径雷达（SAR）系统一般采用经典的匹配滤波器来实现距离维和方位维的二维脉冲压缩变换，其基于匹配滤波器的系统带宽导致系统分辨率常常是有限且固定的.当对输出信噪比和目标时延分辨率有不同要求时，具有可变指数的指数滤波器可根据具体需求在充分保证输出信噪比的情况下产生高于匹配滤波器的目标分辨率.本文基于指数滤波器将距离维和方位维上的二维指数脉冲压缩变换应用于SAR成像算法，即先后将信号通过距离维和方位维指数滤波器，以实现SAR高分辨率成像. 仿真结果表明，该算法在距离维和方位维这两个维度都具有比传统SAR算法处理结果更窄的主瓣宽度和更低的旁瓣高度，有效提高了距离维和方位维的分辨率.

Abstract:

Traditionally the classical matched filter is extensively used in synthetic aperture radar (SAR) systems to achieve the two-dimensional pulse compression of distance and azimuth. Bandwidth of the system is often limited and fixed. In some practical applications, the output signal-to-noise ratio and target delay resolution have different requirements. The exponential filters with variable exponents is a better choice than the matched filter. In this paper, based on the exponential filter, a new two-dimensional exponential pulse compression transform is applied to build the high-resolution SAR imaging algorithm. The simulation results show that the algorithm has a narrower main lobe width and lower side lobe height than traditional SAR algorithm in both distance dimension and azimuth dimension.