超高分辨率机载SAR高精度子带拼接与处理方法研究

Investigation on High Precision Sub-band Synthesizing and Processing Method for Very-high-resolution Airborne SAR

随着合成孔径雷达(SAR)的发展,对目标细节的观测越来越受到重视。SAR图像的分辨率越高,获取的细节信息就越多。目前,一种实用性较高的技术是,利用步进频率线性调频信号波形获取超高分辨率SAR图像。这种技术基于不同子带信号的步进载频关系,通过子带拼接来合成大带宽信号。然而,子带拼接对于基带信号误差非常敏感,该文首先提出一种基于回归和统计学的信号预失真方案。在补偿完子带内的误差后,将子带间的误差转化为一个多变量的优化问题。最后,通过X波段机载SAR系统飞行实测数据验证了所提方法的有效性。

The past decades have witnessed an increasing attention for detailed observation with developing of Synthetic Aperture Radar （SAR）. The higher the resolutions of SAR images are, the more detailed information can be obtained from the images. At the present stage, the stepped frequency chirp signal waveform is a technology with high practicality to achieve the high range resolution imaging. The system can use the stepped frequency relationships between sub-band signals and then the sub-band synthesizing technique is applied to synthesize a large bandwidth signal. However, the sub-band synthesizing technique is very sensitive to the baseband signal error A signal pre-distortion scheme is firstly proposed based on regression and statistics in this manuscript. After compensating the error in sub-band, the problems of errors between sub-bands are transformed into a multi-variable optimization problem. Finally, the effectiveness of the proposed method is verified by the X band airborne SAR system.