Double-base video SAR imaging method based on improved fast backward projection and recursion

Abstract

The invention discloses a bistatic video synthetic aperture radar (SAR) imaging method based on improved fast backward projection and recursion. The method comprises the following steps: firstly, carrying out sub-aperture division and range pulse pressure and up-sampling preprocessing on bistatic SAR echoes; then, an improved rectangular coordinate rapid imaging process is constructed, a geometric correction step is embedded between two-stage spectrum compression, spectrum distortion caused by double-base geometry is corrected on the premise that a coordinate system is kept fixed, and full-resolution sub-images are generated; and finally, based on an infinite impulse response filtering principle, carrying out weighted recursive fusion on the full-resolution sub-image of the current sub-aperture and the historical accumulated image to generate a continuous video stream. According to the method, the low-azimuth-resolution complex image obtained by performing backward projection on each preprocessed data block is subjected to spectrum compression and then is subjected to two times of geometric correction, so that the imaging focusing precision is effectively improved, meanwhile, iterative fusion based on infinite impulse response IIR filtering is performed on the full-resolution sub-image, and the memory I / O bandwidth requirement is reduced.

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