In order to improve the accuracy of motion parameter estimation and imaging quality of moving targets in terahertz Circular Synthetic Aperture Radar(CSAR)mode,a terahertz CSAR ground moving target parameter estimation and refocusing method is proposed.Firstly,the traditional spectral peak measurement method is improved to estimate the azimuth velocity by combining the shadow position of the moving target.Compared with the existing methods,the proposed method takes into account the influence of the real position of the target on the Doppler frequency shift,and improves the accuracy of the moving target's azimuth velocity estimation.Then the Fractional Fourier Transform(FrFt)is employed to estimate the Doppler modulation frequency of the azimuth phase,and the range velocity of the target can be estimated together with the azimuth velocity.Finally,the first-order and second-order phase compensation functions are constructed for azimuth compensation based on the estimation results,and the Phase Gradient Autofocus(PGA)algorithm is utilized to compensate for the residual quadratic and higher phase errors.The moving target motion parameters in the simulated and real CSAR data are accurately estimated and good focusing is achieved,which proves the effectiveness of the proposed method and greatly improves the imaging quality of the moving target.
维普
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