一种改进的多通道重建算法在DPCA-SAR中的应用

The Application of a Modified Multichannel Reconstruction Algorithm to the DPCA-SAR

多通道重建算法常被用于解决离散相位中心天线(DPCA)SAR的方位向非均匀采样问题。然而,当非均匀采样程度非常严重时,传统算法会严重放大天线旁瓣造成的模糊信号及系统噪声功率。提出一种改进的多通道重建算法,该方法通过减少处理频带的个数,将传统多通道重建算法中的适定方程转化为欠定方程,再利用线性约束最小功率法则(LCMP)来最小化模糊信号和噪声功率。试验结果表明,当系统非均匀程度非常严重时,改进后的多通道重建算法能显著提高DPCA-SAR的图像质量。

To settle the problem of non-uniform sampling in the displaced-phase-center-antenna synthetic aperture radar（ DPCA SAR）,multichannel reconstruction algorithm is widely employed. For the strong non-uniform sampling,however,the azimuth ambiguities caused by the antenna side-lobes and the system noise would be drastically amplified by the conventional reconstruction algorithm. A modification is propsed where the number of processed frequency bands is reduced,and then the increased degrees of freedom（ DOF） are exploited to minimize the power of the residual ambiguities and the noise via a linear constraint minimum power（ LCMP） method. Compared with the conventional reconstruction,the modified one dramatically improves the image quality of DPCA-SAR under strong non-uniform sampling situations,which is validated by simulation and real raw data experiments.