Research On Jamming Suppression Of The Dual-point Source Based On Polarization Translation

Due to the merits of high angular measuring velocity and accuracy as well as big data rate,monopulse technique has been widely used in target tracking,precision guidance and other fields.It plays an important role both in civilian and military use.However,dual-point source brings difficulties to the monopulse measurement.When two points locate at a similar range and azimuth with a high similarity of radar echoes,it is hard for monopulse radar to distinguish them precisely.As a result,the angular measurement performance decreases.Meanwhile,radar polarized information has been regarded as an effective way to solve jamming problems.Polarization Vector Translation(PVT)has been put forward and brings enlightenment to enlarge the difference between signal and jamming.If PVT could be applied on angle measurement system,it would be helpful for suppression of jamming in dual-point source situation.Beginning with the principle of monopulse angular measurement,the dissertation studies on the polarization response of the dual-point source.At same time,PVT methods are introduced to carry out the research on jamming suppression of dual-point sources.Thesis discusses three main aspects:1.Polarization response of monopulse angle measurement.Firstly,clarify the principle of monopulse radar in single point source situation and use polarization information to establish a single point source angle measurement model.Then polarization response of dual-point source has been studied,analyzing the effect of the ratio of amplitude and phase difference of echoes from two points.Secondly,analysis the effect of the structure of radar target scattering matrix,polarization receiving antenna and the target fluctuation characteristics on angle measurement.2.The relative theory of PVT.PVT can be classified into two categories: linear PVT and nonlinear PVT.The thesis introduces polarization statement angle,polarization divergence and input-output curve to describe the performance of different PVT methods.Linear PVT realizes the movement of polarization states on Poincare sphere,which do not change the relative position of two samples on Poincare sphere.On the contrary,nonlinear PVT realizes the dispersion or aggregation of polarization states on the Poincare sphere.Comparisons are made between real type PVT and ratio type PVT.The thesis analysis the translation process and the effect of the parameter in translation matrix.Further notes that the limitation of mentioned methods in the separation of the target and the jamming.On this basis,the exponential PVT is proposed,which optimizes the performance of nonlinear PVT.3.Jamming suppression based on PVT.In this part of the study,a measurement method based on PVT is proposed firstly,which is consist of PVT,polarization filteringand monopulse measurement.Then a detailed analysis has been made on the distribution of polarization states,the ratio of jamming suppression and the loss of signal power.At last,the simulation result verifies the effectiveness of the method based on PVT.The results showed that in the situation of dual-point sources,the angle error of the target is significantly reduced.