Research On Micro-Doppler Echo Simulation And Micro-Motion Signature Extraction Technology

The electromagnetic scattering echo of a micro-motion target contains precision micro-Doppler signature information, these information are corresponding with the physical parameters of the target, such as mass distribution, inertial ratio and engine characteristic. These characteristics are always seen as the unique characteristic of the target and playing very important role in the area of target identification. To investigate the simulation of micro-Doppler echo and the signature extraction from targets with micro-motions has significant value in engineering. For micro-Doppler echo simulation, we propose to use the quasi-static method coherent with multilevel fast multipole method to compute the micro-Doppler echo induced by micro-motion body. For micro-dynamic signature extraction, we propose to use an improved high resolution time-frequency analysis algorithm. We use this algorithm to analyze the echo signals that we got from the computing and we got the detail information of the micro-motion body based on the analysis.In the introduction, there are brief reviews and comments of the research background as well as present situation of the subject, and then the main contributions of the dissertation are introduced, in which the frame of the dissertation are particularly pointed out. Coherently, the principle of the quasi-static method is introduced and the procedure of using the multilevel fast multipole method to compute the micro-dynamic echo is presented. After that, we investigate the micro-Doppler signature extraction technology, we presenting the capability of the two instantaneous frequency estimation methods based on the high resolution time-frequency profile, and the micro-motion classification and micro-motion parameter estimation are particularly pointed out.There are specific application researchs of our theory. Firstly, the echo's signature of helicopter is analyzed and the micro-Doppler radar echo induced by real-estate helicopter model's rotating blades is calculated, then the motion signature of helicopter is extracted based on high resolution time-frequency profile. Secondly, we use Independent Component Analysis method (ICA) to investigate the warhead and baits separation in mid- ballistic trajectory. As low resolution radar has no range resolution, there is one way for us to separate the warhead and baits via the differenct motion feature of them, so we need to extract the instantaneous frequency of the warhead and baits precisely. The principal theory and the algorithm of ICA are introduced conceretely and we use ICA method to separate the warhead and baits successfully.The dissertation is concluded with current trends and future outlook in the subject. In particular, some significant and valuable problems are pointed out for further research.