The Micro-motion Characteristic And Combining Classification Of Ballistic Target

As the contrary of ballistic missile, the missile defense (MD) system provides the all-round, multi-level defense for ourselves, and develops a strong deterrent effect for enemy. The MD system is used to ensure that it has no trouble back at home if a"pre-emptive"is taken. Target recognition ability of radar which is the main sensor in the MD system limits the whole system performance. The feature of micro-motion is academically acknowledged as one of the most important features. And In the many recognition methods, the one based on the micro-motion plays the most important part. For the full polarimetric wideband radar, the radar characteristics of midcourse target, the measurability of micro-motion, the micro-motion feature extraction and the fusion recognition of midcourse targets are researched in this dissertation. And some conclusions are validated by the microwave anechoic chamber experiments and the field measurement experiments. The main contents of this dissertation include:In the aspect of radar characteristics of midcourse target: For the typical shape of ballistic missile, the radar characteristics are analyzed and the models of full polarimetric echoes are presented by combining the movement and scattering characteristics.1. Complete model is set for the micro-motion of scattering centers of different positions of the warhead and mathematical expression of the micro-Doppler of the sliding-type scattering center is obtained. The curve of this micro-Doppler is not the generally assumed sinusoid. Dynamic measurement of a precessional target in microwave anechoic chamber is designed for the first time to vividly observe the sliding feature of the scattering center. And the phenomena of the sliding-type scattering center are observed for the first time. This research provides a more accurate model for the micro-motion analysis of precessional warheads.2. For the two kinds of typical shape of ballistic targets, which are rotational symmetric and non-rotational symmetric, the relationship of micro-motion parameters and polarization transformation is modeled. The change of lord and cross polarization components is analyzed under the typical parameters. Then, the models of full polarimetric echoes for ballistic target are presented. The method of describing the attitude angle of precessional target using Euler angle such as yaw, pitch and roll is corrected. The transformation relation between transmit polarization and measurement polarization is established. And it has to be point out that the full-polarization characteristic of targets is indispensable to radar echo simulation of every polarization channel.In the aspect of measurability and extraction of micro-motion: The influence of radar location, performance and movement of target on the micro-motion detecting is analyzed. And some new methods of feature extraction of micro-motion are presented.1. Take the typical missile recognition radar as an example, the influence of some parameters on measurability of micro-motion is analyzed. These parameters include pulse repetition interval, coherent accumulation time, velocity measurement accuracy, the coherence and bandwidth of transmit signal, the location of radar, the precessional angle, the precessional frequency and the orientation of precessional axis. The research provides valuable reference for detecting of micro-motion under the background of missile countermeasure.2. A new method of detection and estimation for micro-motion based on the narrowband tracing information is presented. The parameters of micro-motion can be estimated while tracking. And the algorithm has the following advantages: low computational complexity, high detection probability and high implementability. By the field experiment, some phenomenon is revealed that the length of range profile of rotary target is not usually equal to the radial length of this target. And a new method of feature extraction of micro-motion based on the change of length of range profile is presented. This algorithm has more accuracy and robustness than the traditional assumption using the measured data.In the aspect of recognition of ballistic target: A solution and process framework of fusion recognition of ballistic target is designed. Under this framework, a fusion strategy based on the threat sort is realized. And the relationship of recognition rate between the individual classifiers and the whole system is presented. Even if the number of input targets is 100, and the performance of individual classifiers is low, the system can keep a high recognition rate. The recognition experiments for three different ranges of missile are designed. And the results show that the recognition rate also keeps above 80% even the individual classifier can not find out the missile.This dissertation connected with the application. The algorithms and conclusions in this dissertation are validated by various approaches, such as the theoretical derivation, the simulation experiment, the dynamic measurement in microwave anechoic chamber and the field measurement experiment. Part of the achievements has been successfully used in some applications, and gets good effect.