Harmonic Wave Radar Seeker Target Recognition Technology Research

Modern war's complicated environment required missile can distinguish special target from the interferential cluster.Based on the target's characteristic,the missile can judge whether to hit the target or not.In the field of antiballistic missile field,harmonic wave seeker can distinguish the true target from the faked missile by detect harmonic wave scattered by the target.Studies in this paper were based on the theory of mental target or semiconductor target nonlinear reflection.The theory combined the seeker and harmonic wave radar together which made the seeker could identify the target in intelligent.Harmonic wave seeker 's target identification theory and arithmetic were researched based on harmonic wave scatter model.The main reserarch content and innovation achievements related to the following:For the real metal target and electronic jamming bait were hard to be distinguished by the ordinary radar seeker.Aiming at this problem,the method of using harmonic radar seeker for target recognition was put forward.The radar cross section model and the nonlinear characteristic of metal target and electronic disruptors were analysed.The harmonic wave scattering model of the targets were built.Based on the motion model and harmonic wave scattering model,target harmonic wave scattering coefficient was deduced.According to the calculation of the harmonic wave scattering coefficient of the true target and the electronic disruptors,the harmonic wave radar seeker could identify the authenticity of the target.When the harmonic wave radar seeker receiving target harmonic scattering signal.The detection results were disturbed by the harmonic interference which caused the inaccuracy fitting of harmonic wa ve scattering coefficient.The paper put forward the method to filter the harmonic wave scattering coefficient by digital filter.The wiener filter and the kalman filter were designed to estimate the harmonic wave scattering coefficient of the target.The filtering results of wiener filter and kalman filter were compared.Harmonic wave suppression was analyzed.The results showed that kalman filter had better harmonic noise suppression effect.The real target and metal foil jamming bait was difficult to distinguish because of the similar scattering characteristics.On the issue of this problem,target harmonic wave scattering frequency shift was proposed for target identification.The target's harmonic wave radiation model was built.The target's rotation caused harmonic wave scattering frequency shift which could derivate the frequency shift target function.The target function parameter was searched by genetic algorithm.The algorithm made the seeker could recognize the real metal target and the electronic jamming bait which had rotary motion in the foil cluster.The harmonic wave scattering frequency shift was simulated according to the real metal target and the electronic jamming bait.The simulation results showed that this method not only able to distinguish among the interference from the foil with rotary motion target and electronic jamming device,but also could choose the real target for attack ing according to the different of its harmonic wave scattering frequency shift.Due to the weak scattering target was hard to detect by the harmonic wave radar seeker,the identification method based on the target harmonic scattering of polarized invariants was put forward.By calculating the harmonic wave polarization scattering matrix and its corresponding power matrix,the simulation of target polarization invariants was done.The output of simulation showed that the harmonic wave polarization scattering matrix and its corresponding power matrix could be used as effective features for target recognition.The conventional radar seeker could not distinguish the low altitude target from the electronic decoy.According to this problem,the target hamonic wave scattering signal identification algorithm which was based on the Fourier transform was put forward.The target's frequency spectrum identification algorithm was simulated by using the fourier transform to the target harmonic wave scattering coefficient,adding hamming window,calculating the harmonic power spectrum estimation.The simulation results showed that target identification method in frequency spectrum based on fourier transform could be used as an effective low altitude target recognition method.