Micro-Doppler Features Analysis and Extraction of Vibrating Target in FMCW SAR Based on Slow Time Envelope Signatures

The combination of frequency-modulated continuous wave (FMCW) technology and synthetic aperture radar (SAR) leads to lightweight, cost-effective, and low-power dissipation imaging sensors of high resolution. For extracting the features of vibrating targets on ground in FMCW SAR, the displaced phase center antenna technique is introduced into the FMCW SAR system to suppress the ground clutter, and then, the signal characteristic is analyzed. It indicates that the energy of the joint time-frequency distribution is presented as an uneven distribution that is induced by a slow time envelope (STE). In this letter, a novel extracting method of vibrating features based on STE signatures is proposed. With this method, the vibrating frequency and amplitude can be calculated from some extracted positions in the STE. Some simulations are given for validating the feasibility and effectiveness of the method.