Analysis Of Retrodirective Cross-eye Based On Jammer Platform Rotating

The monopulse radar can use only a single pulse to obtain the angular information of the target, and it is one of the most widely applicable scenarios for the modern tracking radar. Especially in the final stages of a radar-guide missile, using the monopulse radar can be conveniently and accurately measure the position of the target location. The monopulse radar has a strong anti-jamming capability against traditional interference technology. Cross-eye jamming is one of the few methods that are able to produce effective interferences. Cross-eye jamming is an angle deception jamming method which artificially reconstructed glint phenomenon, commonly used in the self-protection of ships and aircraft platforms, can deceive monopulse tracking radar to direct the false target instead of the real target. Using cross-eye jamming, the phase of the signals arrived at the surface of radar is not perfectly inverse. Based on the Van Atta array, retrodirective cross-eye jamming is proposed, which making the phase between the signals is not influenced by the transmission path.Based on extended analysis of retrodirective cross-eye jamming, the initial mathematical model has been established, which expanding the phase shift and amplitude gain. But the mathematical analysis is still in the exploratory stage. The analyses about retrodirective cross-eye available assume that the angle of jammer rotation is settled, and the conditions that the jamming elements may rotate and shake or be pointed in all different directions are not taken into account, in certain cases the effect of retrodirective cross-eye jamming is poor. The researches in the paper all base on range gate pull-off, which removes the influence of the platform skin return. And then, the study will be limited to the case that cross-eye jammer return is isolated. This paper assumes that the angle of jammer rotation is variable, a new scenario is presented which can cause angle deception jamming under these conditions. Meanwhile, multiple linear and multiple-loop structures are introduced into the retrodirective cross-eye jamming. Specifically, the research background and the main achievement of this research are as follows:The first part mainly studies the relative basic theory of cross-eye jamming. Firstly, common angular measurement methods are introduced. The discussions are mainly focused on sum-difference amplitude-comparision and sum-difference amplitude-phase monopulse radar. Secondly, analyses of angle deception jamming against monopulse radar are made, and it highlights coherent and non-coherent jamming. Thirdly, some classical analytical methods, which once applied to glint jamming and can continually be used to cross-eye jamming, are introduced. They include linear-fit analysis and phase-front analysis. Finally, the brief introduction to range gate pull-off jamming which used to pulse radar system has been done. The second part has raised orthogonal single-loop rotating retrodirective cross-eye jamming scenario, and a new criterion called stability factor is proposed to evaluate the ability of cross-eye jamming generating stable angular deception. On the premise of that the angle of jammer rotation is variable, single-loop rotating retrodirective cross-eye jamming is proposed. The mathematical derivation is made for conventional two elements retrodirective cross-eye and single-loop rotating retrodirective cross-eye, and closed-form solutions for the angular error are obtained. Using stability factor as a standard, analyses of conventional two elements retrodirective cross-eye and single-loop rotating retrodirective cross-eye are made, and orthogonal single-loop rotating retrodirective cross-eye jamming are obtained which has the best stability factor. Meanwhile, using typical parameters of a missile threat against an aircraft or ship to do some numerical experiments, the results of the analysis and comparison further prove the superiority of orthogonal single-loop rotating retrodirective cross-eye scenario.The third part mainly studies the jamming tolerance of orthogonal single-loop rotating retrodirective cross-eye, and a new criterion called angle factor specific boundary value (AFSBV) is proposed to determine the range of phase shift and amplitude gain values. On the premise of that the angle of jammer rotation is variable, some classical analytical methods of tolerance, which once used for conventional two elements retrodirective cross-eye, are introduced. Result shows that tolerance analysis based on extended analysis is closer to the actual situation. Using angle factor specific boundary value as a standard, the tolerance analyses about conventional two elements retrodirective cross-eye and orthogonal single-loop rotating retrodirective cross-eye are made, closed-form solutions for angle factor specific boundary value is derived. Meanwhile, comparing conventional two elements retrodirective cross-eye with orthogonal single-loop rotating retrodirective cross-eye, the results show the differences between the two scenarios in the aspect of the nature of mathematics. Through numerical experiments, further superiority evidence of orthogonal single-loop rotating retrodirective cross-eye is got, and the range of phase shift and amplitude gain is acquired in the case of typical parameters.The fourth part mainly studies the improved scenarios of retrodirective cross-eye based on multiple-element and multiple-loop. Because orthogonal single-loop rotating retrodirective cross-eye still has some limiting conditions in the aspect of application, multiple-element and multiple-loop structures are introduced into retrodirective cross-eye scenario. On the premise of that the angle of jammer rotation is variable, two common analytical methods of multiple-element retrodirective cross-eye jamming based on a linear array are introduced, and the result shows that analysis based on extended analysis is closer to the actual situation. Meanwhile, closed-form solutions for the angular error are derived. Using extended analysis method to the proposed scenarios in this part, closed-form solutions for the angle factor specific boundary value are derived. Utilizing stability factor and the range of phase shift which got by the fixed amplitude gain as a standard, further superiority evidence of the proposed scenarios in this part is obtained through comparing the proposed scenarios in this part with conventional scenarios.