多相滤波在合成孔径雷达数字正交解调中的应用

The Applications of Polyphase Filtering in Digital Quadrature Detection of SAR

在一般的雷达和通信系统中,实现中频或射频的直接采样,需要完成数字正交解调过程,数字乘积检波(DPD)是实现数字正交解调的一种工程上易于实现的方法,但该方法获得的I/Q数据是需要修正的。该文结合合成孔径雷达信号处理,提出了多相滤波法来修正通过DPD获得的I/Q通道数据,并和Bessel滤波进行了比较。仿真实验结果表明,该方法简便灵活,且工程上易于实现;在滤波器阶数相同的情况下,多相滤波器的最大绝对修正误差为5.8394×10--4,而Bessel滤波的最大绝对修正误差为9.307×10-4,而且,多相滤波很容易实现非等距滤波。

In a general radar and communication system, the digital quadrature detection is necessary for implementing direct IF or RF sampling. The Digital Product Detection (DPD), applied easily in a real engineering, is a method to implement the digital quadrature detection. But the datum acquired by the method should be corrected. The paper presents the polyphase filtering to correct the I/Q datum acquired in combination with the Synthetic Aperture Radar (SAR) signal processing by contrast with Bessel filtering. The simulation results show that the method is simpler, more flexible and applied easily. The correct error by the polyphase filter with the same order is smaller than the error by the same order Bessel filter. The former maximum absolute error is 5.8394×10-4. The latter maximum absolute error is 9.307×10-4. In addition, the polyphase filtering can implement the unequal interval filtering easily.