数字合成孔径雷达中改善I/Q通道不平衡性的多相Kaiser滤波法

Polyphase Kaiser Filter for the Correction of I/Q Imbalance of Digital Synthetic Aperture Radar

该文分析了数字合成孔径雷达正交相干检波的I,Q通道的不平衡性,给出了评价I/Q通道不平衡性的统一指标。为了改善数字合成孔径雷达I/Q通道的不平衡性,该文采用了一种新的方法——内插多相Kaiser滤波法.研究表明,当多相Kaiser滤波器的阶数为16时,噪声旁瓣的抑制比为-74dB,相对瞬时频率误差为-1.18％。

The principle of the quadrature coherent detector of the digital Synthetic Aperture Radar (SAR) is introduced in the paper. The imbalance of its I/Q is analyzed, and the uniform index of its imbalance is presented. For the correction of the digital SAR I/Q imbalance, the paper adopts a new method-interpolation polyphase Kaiser filter. The results show that when the stage of the polyphase Kaiser filter is 16 the ratio of sidelobe suppression is -74dB, and the relative instant frequency error is -1.18%.