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采用双基地逆合成孔径雷达距离-多普勒算法成像时,目标尺寸较大或累积转角过大,会引起越分辨单元徙动现象,影响成像质量.针对双基地角时变下逆合成孔径雷达成像的越分辨单元徙动问题,提出了一种校正算法.首先,建立了双基地逆合成孔径雷达回波模型,分析了越分辨单元徙动的产生机理,并通过广义的Keystone变换实现了越距离单元徙动的校正,同时消除了目标非匀速转动对成像的影响.然后,基于图像对比度最大准则估计了图像的等效旋转中心位置,并对距离向绝对定标,进而构造补偿相位项,完成了越多普勒单元徙动的校正.仿真实验结果表明,此方法能够有效地校正双基地角时变下的越分辨单元徙动,提高成像质量.
When using bistatic Inverse Synthetic Aperture Radar Distance-Doppler imaging, the target size is larger or the cumulative rotation angle is too large, which will cause the more resolved unit migration and affect the imaging quality.Aiming at the time-varying inverse synthetic aperture radar Aiming at solving the problem of cell migration in imaging, a correction algorithm is proposed.Firstly, a bistatic Inverse Synthetic Aperture Radar (EAR) echo model is established and the generation mechanism of the discerned cell is analyzed. The generalized Keystone transform The distance from the unit to the migration of the correction, while eliminating the target non-uniform rotation of the imaging impact.And then, based on the maximum image contrast criterion to estimate the equivalent rotational center of the image location, and the absolute calibration of the distance, and then construct the compensation phase term, The correction of more Doppler unit migration is completed.The simulation results show that this method can effectively correct the migration of the discernable units and improve the imaging quality under bistatic angular variation.