Abstract: The pulse compression result will be distorted while the target moves very fast and it cannot get right ISAR images. A novel algorithm based on chirp-Fourier transform was proposed to solve this problem. In the scheme, every echo’s differential frequency signal of stretch processing was calculated by chirp-Fourier transform to estimate the target’s location and speed, and the target’s precious speed could be averaged by the estimations during the whole dwell time. Then the penalty function could be constructed to eliminate the intra and inter-pulse motion, and it could get right ISAR images. Because the chirp-Fourier transform was completed during the pulse repetition period, the algorithm could meet the real-time requirement. Further more the algorithm could simultaneously accomplish moving parameters estimation and imaging. The algorithm has the advantages of simple structure and strong anti-noise ability, so it is easy to implement in Engineering.

Key words: ISAR imaging, stretch method, LFM, chirp-Fourier transform, motion parameter estimation