Modeling Of Radar Polarization Effects Of Low-altitude Target Glint And Suppression Techniques

Low altitude and ultra-low altitude penetration is an effective tactics of aircraft and cruise missiles to avoid radar detection.In the case of low-altitude,the multipath effect becomes the primary factor that affects the radar detection accuracy.Therefore,the multipath effect and its suppression techniques become hot and difficult topics in the low-altitude anti-missile problem.In the case of specular multipath,the reflected signal and the direct signal are simultaneously received by radar.There is a little difference in elevation angle between target and image.The reflected signal is highly coherent with the direct signal.The principal errors in tracking radar appear in the elevation coordinate.It is the key to improve the radar detection accuracy of elevation measurement by establishing accurate two-point glint model for low-altitude target.As an important parameter to characterize the vector characteristics of electromagnetic wave,polarization is another important information except space domain,time domain and frequency domain,which is closely related to the radar detection process.As the image and the target can't be simply differentiated in the space and time domain,therefore,this paper focuses on the influence on elevation errors of the polarization domain characteristics of the image,target and radar antenna.In this paper,a new polarization diversity technique is designed to suppress the angle measurement error.The main contents of this paper include two aspects:1?Modeling of radar polarization effects of low-altitude target glintBased on the classical two-point source glint model,the effects of radar antenna polarization,target polarization scattering matrix and specular reflection coefficient on radar angle measurement are analyzed.The antenna polarization effects model of low-altitude target glint is established.This paper analyzes the differences in the polarization characteristics of image and target.The radar polarization effect model is established for both ground-based radar/carrier radar and airborne radar/missileborne radar scenarios.The influence of radar receiver polarization on radar target glint is studied emphatically.The difference between the image and the target polarization characteristic is summarized,which provides the reference and basis for the radar low-altitude target glint suppression technique.2?The suppression of the low-altitude target glint by polarization diversity techniqueBased on the polarization effect model of target and image glint,the polarization diversity suppression method is studied.Firstly,the basic method of polarization diversity is expounded,that is,the angle measurement error suppression is carried out by analyzing and using the characteristics of positive and negative offset of target glint.The radar polarization diversity method and parameters are designed for slow fluctuation target and fast fluctuation target respectively.Through the theoretical analysis and simulation of the polarization diversity technique,and compared with other polarization diversity methods,the availability of the polarization diversity method is verified.