Study On Polarization Anti-jamming With Terminal Guidance Radar

Most of the existing terminal guidance radars work in the unipolar state.Active interference is mainly suppressed in the time domain,frequency domain and spacial domain,but the polarimetric information is useless.With the continuous progress of science and technology,radars are difficult to identify and inhibit some active interference in the time domain,frequency domain or spacial domain.We need some new aspects to make interference suppression,such as polarization domain.Therefore,we can use the difference of polarization characteristics between targets and interference to suppress the interference.And this technology will become a powerful means of anti-jamming with the terminal guidance radar.In this thesis,combined with a fund project,we study on the polarization anti-jamming technology of terminal guidance radar based on the previous work.The specific work is as follows:1.Research on the signal orthogonality and basic knowledge of polarization.First of all,we summarize the definition of polarization,the description of polarization state parameters,the representation of target polarization scattering characteristics and the three kinds of polarization measurement methods.The application range,advantages and disadvantages are given.Secondly,we analyze the orthogonality of the orthogonal frequency division pulse signal and the positive and negative slope linear frequency modulation signal.The results show that the orthogonality of the orthogonal frequency division pulse signal is better than the positive and negative slope linear frequency modulation signal.2.Research on polarization filtering technology.We discuss the polarization filtering technology from two aspects: estimation of the polarization parameters;the design of the polarization filter.In the first aspect,the polarization coherence matrix estimation and its recursive estimation method for adaptive polarization filter are studied.A frequency domain-polarization domain joint estimation algorithm is also introduced.The accuracy of polarization parameters estimation is verified by Matlab simulation.In the case of polarization filters,single-notch polarization filters,multi-notch logic-product filters and spectrum polarization filters are introduced.The performance of the filters is simulated and its application range is given.3.Simulation of polarization anti-jamming system for terminal guidance radar.We construct the system model of terminal guidance radar.For the noise jamming,we use orthogonal frequency division pulse signal and positive and negative slope linear frequency modulation signal as a transmission signal.The results show that the polarization anti-jamming capability of the orthogonal frequency division pulse signal is better.Secondly,we analyze the influence of the cross-polarization effect on interference suppression and angle measurement.The measurement methods for cross-polarization of different systems are given.Finally,the method of suppressing the cross-polarization angle deception based on auxiliary antenna for mono-pulse radar is deduced.The principle of angle measurement by mono-pulse radar and cross polarization angle deception is analyzed.Then we use the signal of auxiliary antenna and main antenna to suppress interference by taking example of the side-lobe cancellation method.The simulations verify the effectiveness of the method.