Research On Jamming Method Against Multi-channel SAR-GMTI And Jamming Effect Evaluation

As a microwave imaging radar,synthetic aperture radar can obtain high quality images of static target areas under terrible conditions such as cloudy,heavy rain,thick fog and so on.It is an important way in the field of information perception and is widely used in military reconnaissance and battlefield situational awareness.Combining it with the ground motion target detection technology,it can monitor the static and dynamic information in the scene at the same time,which is an important technical means to obtain the enemy's military dynamics on the battlefield in the future.Given the powerful information access capabilities of SAR-GMTI systems on the battlefield,countries are actively looking for effective methods of interference.The SAR-GMTI radar has strong suppression ability to suppress interference,and active deception jamming technology has become the key research direction of SAR-GMTI radar.To improve the stability and robustness of the current SAR-GMTI spoofing interference method,this paper deeply studies the SAR-GMTI high fidelity active spoofing interference method,and puts forward the corresponding interference effect evaluation method.The main work of this paper is listed as follows:(1)Aiming at the problem that the false target generated by the traditional single jamming machine will be located near the azimuth of the jammer by the multi-channel SAR-GMTI system.Firstly,the process of processing deception jamming signals generated by single jammer in multi-channel SAR-GMTI system is derived.Then according to the cause of its positioning error,the spoofing method with double jammer coordination is proposed.By adjusting the amplitude coefficient ratio of the two jamming machines to generate the spoofing interference signal,the synthesized false moving target signal disappears compared with the additional phase of the real signal,showing the same positioning characteristics as the real target.However,the formula for solving the ratio of amplitude coefficient is transcendental equation,and it is difficult to be used in engineering practice without accurate analytical solution.In this paper,a mathematical model of the additional phase in the false motion signal after modulation is proposed.The model can quickly solve the parameters needed for the modulated spoofing interference signal and implement effective interference.(2)The evaluation of deception jamming effect is an indispensable part of deception jamming process.Accurate and effective evaluation method is an important support to optimize interference mode and improve the performance of interference equipment.Aiming at the problem that the existing evaluation methods are not suitable for multi-channel SAR-GMTI deception jamming,this paper proposes to construct the evaluation function based on the evaluation criteria of detection probability,positioning accuracy and image quality.The detection probability is based on the ability of the SAR-GMTI system to detect the target.The evaluation of positioning accuracy is realized by calculating the target offset distance based on the minimum mean square error algorithm and calculating the target offset angle based on the minimum entropy criterion.The speed influence factor of moving target should be added as one of the indicator when evaluating the imaging quality of a conventional SAR image.The evaluation function uses AHP to give the corresponding weight to its parameters,and the evaluation results of deception jamming effect can be obtained by weighted calculation of all parameters.Finally,the jamming effect is analyzed based on the reconnaissance parameter error of the reconnaissance system,and a comprehensive evaluation of the deception jamming effect of SAR-GMTI can be obtained.