Radar Target Micro Parameter Extraction Method Research

The micro-motion parts of target may induce frequency modulation on the radar echo, which is called micro-doppler effect. Micro-doppler character is considered as one of the most important characters for target recognition because of its uniqueness. The micro-doppler character contains micro-structures and micro-dynamics information of the target, so it can be applied widely to target recognition, life detection, counter terrorism, etc.The concentration of this paper is micro-doppler parameters estimation. The main problems are studied as follows:1. According to the mathematical model of micro-motion point target, the impact of micro motion parameters, initial state, and centroid translation on the micro-doppler are analysed. The unified expression form of micro-doppler signal is proposed, which is the basis for further study of extracting micro-motion parameters.2. Aim at the effect of centroid translation on extracting the parameters of micro-motion target, a method to eliminate the influence of centroid translation is proposed, a method to extract the micro-doppler parameters based on instantaneous frequency curve is also proposed.3. The performance of matched Fourier transform is verified by extracting the micro-doppler parameters. The analyzed results show that the approach can be used to extract the parameters of multi-component micro-doppler signals at low Signal-to-Noise Rate; in addition, it has good resolution in both frequency and amplitude.4. According to the characteristics of time-frequency distribution of micro-doppler signals, the micro-doppler parameters are estimated by Wigner-Hough transform at low Signal-to-Noise Rate condition. The simulation results show that the approach has good estimation accuracy and it is robust to noise.5. Considering the traditional methods are invalid in extracting the parameters of partial micro-doppler signals, three-point model method and polynomial fitting method are introduced. The simulation results show that both two methods can be used to extract micro-motion parameters from fraction of the period. The relative theories and algorithms are verified by simulations, the results reveal that the methods can ertract micro-motion parameters effectively.