An On-Board Imaging Processing Algorithm for Stripmap Mode of Azimuth Multichannel Spaceborne SAR

In the traditional processing methods of azimuth multichannel spaceborne synthetic aperture radar (SAR), the azimuth spectrum reconstruction and subsequent azimuth focusing are always via full-aperture processing. However, if the multichannel full-aperture echo data are stored on the satellite, and then the full-aperture algorithms are used for the on-board imaging processing, the huge amount of echo data will require more on-board storage resources and computing resources, and the imaging processing time will become longer. To solve the above problems, a novel on-board imaging processing algorithm via the idea that the data acquisition and the on-board imaging processing of the subaperture data are carried out simultaneously is proposed in this article. In the algorithm, the azimuth spectrum ambiguity is eliminated by the subaperture azimuth spectrum reconstruction. Then, the range cell migration correction (RCMC) and the range compression for the unambiguous subaperture signals are accomplished by the chirp scaling algorithm (CSA). After that, the low-resolution subaperture images are got via the subaperture focusing. By coherently combining all subaperture images, the final result with high resolution of all echo data can be obtained. Finally, the simulation for the point targets is given to verify the effectiveness of the proposed algorithm.