Experimental Study Of The Composite Vibration Laser Micro-doppler Effect

Laser radar micro-Doppler effect has good application prospects in the detection and identification of for it's high measurement precision and strong anti-interference ability. Because complex vibrating targets are more complex than single-frequency targets, so it is more practical to research the feature extraction and identification of complex vibrating targets. Firstly, a detecting system based on Michelson-Morley dynamic interferometer for laser micro-Doppler effect of the complex vibration was designed and built, some experiments have been done. The experiment signals were analyzed using a method of joint time-frequency analysis. Through the comparison of several different time-frequency analysis methods, it is shown that the time-frequency image which is gotten by reassigned spectrum picture distribution has much ideal time-frequency characteristics, this method is fit for the analysis of micro-Doppler signal induced by target complex vibration, some features of the complex vibrating target can be extracted from the time-frequency image. The comparing of micro-Doppler experiment results of single-frequency vibrating target and double-frequency vibrating target testifies the validity and reliability of using our experimental system and time-frequency method to extract the complex vibrating frequency of target. Secondly, a mathematical model for detecting the complex vibration of moving target by micro-Doppler effect in laser radar was built, then simulation research for laser micro-Doppler effect of the complex vibrating target was conducted using MATLAB, and the time-frequency analysis of reassigned spectrum picture was used for simulated signal. In the same cases of experimental parameters, the micro-Doppler signal of complex vibration was simulated and it agreed with the experiment results very well. The validity of the mathematical model was confirmed by the comparison of simulation results and experiment results.