Research On Radar Target Glint Modeling And Suppression

Target glint is the main factor which influences tracking and guidance accuracy of terminal guidance radar. Researchers on radar precision guidance weapon pay much attention to suppress glint, improve angle measuring accuracy and improve guidance radar's tracking and guiding accuracy. In this paper, the theory and some application techniques about target glint for terminal guidance radar in optical region, including glint modeling, glint suppression, and target tracking with glint are discussed in detail. The main work is outlined as follows.In the introduction, the researching background is introduced firstly. The status and role of radar precision guidance weapon in local war under condition of future advanced technique are clarified, with an emphasis on the terminal guidance technique, which educes the concept of the radar target glint. Next, the relevant theory and researching actuality of the radar target glint are summarized. The whole paper's major work is presented at last.In chapter 2, the glint modeling of the missile target is mainly studied. The principle of phase gradient method using for glint modeling is introduced firstly. Then based on the two-dimensional GTD scattering centers model of the missile target, the modeling approach to the missile target glint is discussed. Meanwhile, the two-dimensional determinate model of glint linear deviation is obtained. Finaly the glint linear deviation data are obtained from computer simulation based on the glint determinate model. The analysis of these data shows the relationship between glint linear deviation and target RCS, also verifies that glint linear deviation obeys non-Gaussian distribution.In chapter 3, the problem of glint suppression based on polarization diversity technique is mainly studied. First of all, the principle and application of several radar diversity technique is introduced. Then it is focused on the problem of glint suppression using polarization diveristy. Based on the glint linear deviation model in chaper 2, the computer simulation shows that the glint linear deviation data, which obtained from four different linear polarization mode respectively, are almost irrelative. According to this, the use of the weighted average method to deal with those data in different linear polarization mode can effectively suppress the target glint. Computer simulation verifies the effectiveness of the method.In chapter 4, the problem of glint suppression based on frequency-domain high-resolution profiling technique is mainly studied. The profiling technique can be used to separate target's scattering centers, then the independent information of single scattering center can be used to angular information processing, which can suppress target glint. First of all, the principle of two kind of approach to profiling, which are time-domain high-resolution system and frequency-domain high-resolution system, are introduced. Next, the qualification of achieving frequency-domain profiling in a given condition is theoretically analyzed. Finally, an frequency-domain monopulse amplitude comparison angle measurement algorithm based on FFT is deduced. The algorithm not only ensure the angle measurement accuracy, but also can suppress the glint due to the separation of scattering centers. Computer simulation verifies the feasibility of the algorithm used to angle measurement.In chapter 5, the problem of glint suppression based on signal preprocessing technique is mainly studied. The purpose of signal preprocessing is suppressing glint before Kalman tracking filtering, removing the spike, and whitening the glint noise in order to fit to the following standard Kalman tracking filtering. Firstly, two statistical glint model usually used to engineering application is introduced. Next, a new preprocessing method to suppress glint noise using Expectation-Maximization(EM) algorithm is proposed. The core of the method is pre-estimating the target position using EM algorithm based on feedback structure. Finally, the performance of the new method is theoretically analyzed. Computer simulation verifies the good perfermance of the new method.In the end, the whole paper's researching work is summarized, and some researching conclusions are presented. At last, some further researching works to be done are introduced.