Characteristic Parameter Extraction Of Ballistic Missile Based On HRRP And Micro-Doppler

The feature extraction of ballistic missile target is very important in the warhead recognition,in which the precession period and the precession angle play an important role in distinguishing the warhead from the heavy decoy.In this paper,the extraction of the precession characteristic parameters is studied in terms of the periodicity of the HRRP,the radial length of the warhead and the feature of micro motion.The major research work and results of this paper are as follows:(1)The time domain and frequency domain models of radar echo of ballistic missile are established.The characteristics of Doppler echo are analyzed.The problem of one-dimensional range profile and radial length extraction of warhead is studied.The simulation results show that the extraction of one-dimensional range image,the compensation effect of motion-induced frequency shift and the extraction of radial length under different signal-to-noise ratios and different bandwidths are verified.(2)A method of predicting precession period based on HRRP maximum cross correlation function is studied.Considering the effect of high-speed translation and precession on one-dimensional range profile,the precession model of the middle section of the warhead is established.The maximum cross-correlation function of one-dimensional range image is transformed by FFT,and the transformed result is subjected to the approximate sine wave frequency offset correction processing to extract the precession period.The frequency threshold is used to correct the non-frequency resolution integer precession frequency,which improves the extraction accuracy of the precession period.The influence of different precession period,different observation duration and different signal-to-noise ratio on precession period extraction accuracy is verified by simulation.Compared with the traditional method,the method has higher precision and better anti-noise performance.(3)A method of feature extraction for ballistic missile based on radial length cost function optimization is proposed.The precession model and the radial length model are established.The cost function of the radial length is given,and the precession period extracted from the frequency offset correction method is taken as the initial value,and the radial length at each attitude angle extracted in the text is taken as the training set.The gradient parameters are used to update the characteristic parameters.Finally,the parameters such as precession angle,precession period,cone height,bottom radius,azimuth angle and pitch angle are obtained.Through the simulation analysis,compared with the existing methods of extracting the characteristic parameters,this method improves the extraction accuracy of the precession period by more than an order of magnitude.(4)Aiming at the micro-Doppler feature extraction of ballistic missile warheads,a method of extracting the precession period using the time-frequency spectrum is proposed.The vibration,swing,rotation and precession micro-Doppler models of the warhead are established,and the micro-Doppler features under various motion forms are analyzed.The time-frequency spectra are obtained by short-time Fourier transform and Wigner-Weir transform.The time-frequency spectrum is rearranged,and then the peak distribution value is extracted to obtain one-dimensional time-frequency curve,and autocorrelation and amplitude difference processing are carried out to extract the precession period.The effects of different observation time and different signal-to-noise ratio(SNR)at different carrier frequencies on the precision of the micro-motion period are simulated.Compared with other methods in the literature,this method has higher precision in different observation time and low SNR.