| In the rapid development of electronic warfare technology today,with the development of new radar and the complication of electromagnetic interference,it is of great significance to study the radar anti-jamming technology in order to improve the anti-jamming ability of radar and reduce the influence of jamming on radar detection.This thesis takes phased array radar as the research object and focuses on active mixed jamming suppression algorithms based on blanket jamming and deception jamming.Firstly,the active mixed jamming model for phased array radar is built.Then,the analysis and simulation of the phased anti-jamming algorithm for conventional phased array radar,the traditional phased array radar signal process has been found problematic since the deception jamming cannot be effectively suppressed when the pressure blanket jamming is mixed with deception jamming.In this thesis,an improved algorithm based on auxiliary-path weighting is proposed.The simulation verifies that it does not only solve the corresponding problem effectively,but also enables the radar to accurately identify the real target in the case of the weak blanket jamming and deception jamming.Secondly,there is another problem that the phased array radar is confused by mixed jamming in complex environment.Therefore,an active mixed jamming suppression algorithm based on minimum variance distortionless response and sample matric inversion(MVDR-SMI)and an active mixed jamming suppression algorithm based on subspace projection(SP)are proposed.Both of the above algorithms are obtained by using the correlation matrix estimated by antenna echo signal and then using the adaptive weighting vector to weight the echo signal based on the corresponding algorithm.The simulation and deduction verify that the two algorithms make the antenna pattern in the main beam direction form strong power and in the direction of interference form a deeper nulling.At the same time,both of the two algorithms are simple and adaptable in the process of suppressing the active mixed jamming.Finally,this thesis is concluded by comparative analysis.Firstly,the step to step suppression algorithm for the active mixed jamming based on auxiliary-path weighting has the deepest nulling in contrast to the other two algorithms in power pattern about the blanket jamming.Secondly,on the premise that the jamming subspace of the antenna echo signal can be estimated effectively,the active mixed jamming suppression algorithm based on SP is superior to the other two algorithms in interference cancellation ratio.Thirdly,in the case of high interference plus noise power ratio(INR),the step to step suppression algorithm for the active mixed jamming based on auxiliary-path weighting is better than the other two algorithms.However,in the case of low INR,the active mixed jamming suppression algorithm based on SP has better ECCM improvement factor(EIF).Finally,in the limitation of the algorithm,the auxiliary-path weighted method is used for radars with auxiliary antennas and the number of auxiliary antennas is greater than or equal to 3,and the MVDR-SMI method is used for radars that have a sampling point in the pulse repetition period(PRT)that is greater than the number of antenna elements twice times,and the SP method is used for radars in environments where the mixed jamming gain is greater than the target signal and the gain of the target signal is equivalent to the noise gain. |
