Compensation for High-Frequency Vibration of SAR Imaging in the Terahertz Band Based on Linear Chirplet Transform and Empirical Mode Decomposition

SAR in THz band is very important and valuable in the field of radar signal processing, and it is much sensitive to the high-frequency vibration of the platform due to the short wavelength. In this article, the high-frequency vibration is characterized as a multicomponent SFM signal, and the parameters estimation method based on the linear chirplet transform and empirical mode decomposition is proposed to compensate for the high-frequency vibration errors. This method can extract the instantaneous frequency of the received signal with high precision, and the focused SAR image can be obtained consequently. Results of simulated and real measured data are provided to illustrate the effectiveness of the novel algorithm proposed in this article.