机载合成孔径雷达大斜视高分辨率重叠子孔径成像算法研究

Study on High Resolution Overlapped Subaperture Imaging Algorithm for High Squint Airborne SAR Processing

该文提出了一种结合图像二维几何失真校正和空变相位误差补偿的大斜视、高分辨率机载合成孔径雷达重叠子孔径成像处理方法。其运动补偿过程不需要实时调整雷达参数,易于工程实现。整个成像处理过程融合了基于频谱分析的分步变换技术,以线性距离多普勒算法生成子孔径图像为前提,根据转台成像的基本原理,通过固定参考系下地理坐标的变换和定位,实现了不同子孔径图像之间散射点的距离和多普勒对准,并有效地补偿了空变剩余相位误差。点目标仿真和实测数据成像结果证明了该处理方法的有效性。

A high-resolution subaperture imaging algorithm incorporated with the correction of 2-D image geometric distortion and the compensation of spatially-variant phase error for high squint airborne synthetic aperture radar is presented. Each subaperture processing is based on linear range-Doppler algorithm. According to the basic theory of rotating-object imaging, a methodology is developed to realize the range and Doppler alignment of the corresponding scatterers in successive subimages by the geographical coordinate transforming and positioning, while the step transform technique based on SPECAN is employed to obtain the high-resolution image. The point-target simulations and live data processing results show the validity of the proposed approach.