A Micro-Oscillation Signal Extraction Method for Radar Target

Micro-vibration measurement based on broadband radar is one of the typical non-contact vibration measurement methods. It has the advantage of working all-weather. It plays an important role in many fields such as safety monitoring of highway/railway bridges, vital signs measurement, target recognition and so on. The typical radar vibration measurement model is based on the phase derivation model, that is, the linear dependence of the phase change of the target echo and the target vibration. When the target is in a strong clutter environment, the target vibration modulation signal in the radar echo phase is weak and easily submerged by the phase noise of the system, so it is difficult to be extracted accurately. In order to solve this problem, a method of extracting weak target vibration based on slow time difference conjugate multiplication is proposed in this paper. Firstly, the target high resolution echo is slowly time-differentiated. Then, the difference result is multiplied by the target echo conjugate at the current time, and the real part is taken. Finally, the vibration signal on the target is obtained by integrating. This method is suitable for high precision micro-vibration extraction of targets without macro-motion.