The Micro-motion Characteristics Extrction Of Ballistic Target In Midcourse Based On Hrrp

The ballistic missile target recognition technology is a much important research content to ballistic missile defense system. It is a precondition for missile intercepting to identify the warheads from the incoming target groups accurately. The midcourse of ballistic missile flight is a key stage to identify real and artificial warhead, because it takes the longest time of the warhead flight. Sequential HRRPs of ballistic midcourse target contain the micro-motion features of target, which can be used to distinguish the warheads and decoys. In this dissertation, three different ways to extract the parameters of micro-motion target are discussed based on HRRPs of ballistic midcourse target by analyzing the micro-motion features of missile target. The main research contents include:1. The micro-motion models of ballistic midcourse target, including precession, nutation model of cone warhead and swing, tumbling model of cone decoys, are established. By analyzing the micro-motion features of ballistic target, radar micro-Doppler expression of different micro-motion states is derived. It is proved that micro-motion features can be used to distinguish the warheads and decoys effectively by comparing the difference between the micro-Doppler of different micro-motion.2. The micro-motion parameters estimation method based on two-dimensional graphic detection is studied. This method gets the precession frequency estimation curve using HRRPs’ weight and calculation directly, and using MUSIC method and nonlinear least squares Gauss-Newton method to estimate the precession frequency respectively. In addition, this method estimates the precession angle based on the curve detection function of generalized Radon transform.Compared with traditional RCS Polynomial fitting method, the estimation precision is improved, and don’t need to obtain the target’s physical structure.3. In order to solve the problem that the computational complexity of two-dimensional graphic detection method rises along with the number of curve parameters and precision demand, the ballistic midcourse target micro-motion parameters estimation method based on the radar line of sight(RLOS) distance of the cone scatters is studied. This method extracts the RLOS distance curve of scatters using trace point and track match method. On one hand, extracts precession frequency in scatter’s RLOS distance curve, on the other hand, estimates the precession angle of ballistic midcourse target by extracting the extreme value of RLOS distance and using the geometrical relationship.4. In order to improve the precision of parameter estimation, the precession parameter estimation method is studied. This method estimates the precession frequency and angle using the position difference sequence between the scatter which always faces RLOS and the top scatter of the cone. Compared with the precession angle estimation method using RLOS angle change among long time interval, the precision and stability are improved.