多模式斜视多通道SAR成像方法

Squinted Multichannel SAR Imaging with Several Modes

方位多通道技术是当前合成孔径雷达(SAR)系统主流的高分宽幅实现方式。而将方位多通道技术与斜视波束扫描(聚束、滑动聚束、TOPS)工作模式相结合可以实现灵活的更高分辨率或者更宽幅宽的遥感观测。然而由于斜视以及波束扫描会使得回波信号的多普勒带宽远大于通道数与脉冲重复频率(PRF)的乘积,使得传统的多通道成像方法失效。为了解决上述问题,本文提出一种基于方位去斜加方位重采样的多模式斜视多通道SAR成像方法,该方法通过对各个通道信号分别进行方位去斜以及对去斜、线性距离走动校正(LRWC)后的信号进行方位重采样来解决方位时变的问题,使得传统的多通道成像方法可以使用。理论分析与实验结果均验证了该方法可以处理多模式的斜视多通道SAR数据,并且得到聚焦良好的图像。

Azimuth multichannel technology is the mainstream implementation method of high resolution and wide swath in synthetic aperture radar(SAR)systems.The combination of azimuth multichannel technology and squint beam steering mode(spotlight,sliding spotlight,TOPS)can realize flexible remote sensing observation with higher resolution or wider swath width.However,due to the existence of squint angle and beam steering,the Doppler bandwidth of the echo is much higher than the product of the number of channels and pulse repetition frequency(PRF),which makes the traditional multichannel imaging methods ineffective.To solve the above problems,a squinted multichannel SAR imaging with several modes based on azimuth de-squinting and azimuth resampling is proposed in this paper.This method solves the problem of azimuth time variation by de-squinting the signals of each channel and azimuth resampling the signals after de-squint and linear range walk correction(LRWC),so that the traditional multichannel imaging methods can be used.Theoretical analysis and experimental results show that multi-mode squint multichannel SAR data can be processed by this method and well-focused images are obtained.