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Synthetic Aperture Radar Micro-doppler Characteristics

Posted on:2010-03-21Degree:MasterType:Thesis
Country:ChinaCandidate:L DongFull Text:PDF
GTID:2208360275983947Subject:Signal and Information Processing
Abstract/Summary:PDF Full Text Request
A new academic system called micro-Doppler which is put forward by the famous scholar Victor C.Chen is developing on the basis of micro motion of the object. Since micro-Doppler phenomenon is observed in radar target detection, micro-motion, as one of significant target characteristics with promising applications in radar target feature extraction and recognition, increasing attentions and research interests. The backscatter of a target with micro-motions contains fine micro-Doppler features, which enables us to determine some unique properties of the target. Base on these, this dissertation has done some research on the micro-Doppler effect in SAR. The contributions are caculated as following:1. Based on the micro-Doppler effect of radar, the micro-Doppler model and the mathematical formulas of micro-Doppler are analyzed in the common static radar, the micro-Doppler model and the mathematical formulas of micro-Doppler are also derived in SAR.2. The micro-Doppler effect of the vibration and rotation is firstly discussed which is depend on the specific micro motion such as vibration and rotation. The mathematical formulas are derived, and the micro-Doppler signatures of targets undergoing simple sinusoidal vibration and rotation are simulated. By comparing the theoretical results and simulated results, the accuracy of the derived theoretical results are confirmed.3. In order to analyze the time-varying frequency characteristics of the micro-Doppler modulation, the signal must be analyzed by using a high-resolution time-frequency transform. In this paper, the Fourier transform, the short-time Fourier transform, the Wigner-Ville distribution, the pseudo-Wigner-Ville distribution, the smoothed pseudo-Wigner-Ville distribution, and the rearrangement of the smoothed pseudo-Wigner-Ville distribution are all used. The simulation experiments are presented in this article, and the results testify that the the rearrangement of the smoothed pseudo-Wigner-Ville distribution satisfy the requirements on high resolution in both the time and frequency domains and low cross-term inteference.4. In order to effectively extract micro-Doppler features from the returned SAR echo, two methods are proposed. One is based on the wavelet transform, and the other is based on empirical mode decomposition.5. Finally, the trend of application is summarized , the need for study and the problems are pointed out.
Keywords/Search Tags:synthetic aperture radar, micro-doppler, time-frequency analysis, wavelet transform, empirical mode decomposition
PDF Full Text Request
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