Millimeter Wave Active Phased Array Radar Anti-jamming Technology Research

The millimeter-wave active phased array (MMW-AESA) radar which performs wellon the multi-target rapid identification and tracking equipped on kinds of platforms withhigh precision for long distance，has been a research hotspot and widely used in thespace-object detection and related field. The identification precision desired by theplatforms is pretty high, which means that there is a higher demand for improving theradar anti-jamming performance，and enervating the impact caused by active jammingfrom sidelobe on measurement and guidance accuracy. The spatial measures toanti-active-jamming such as sidelobe cancellation (SLC), sidelobe blanking (SLB), andbeam pattern shaping if introduced will make good sense to improve the radar detectionperformance effectively. This thesis studied on the performance of the measuresmentioned above when introduced in the MMW-AESA radar, mainly focused on thefollowing aspects:Firstly， the SLB system detection performance with the target or jammer modelsbased on constant model, chi-square distribution, noncentral chi-square distribution,noncentral Gamma-Gamma distribution is analyzed, and then based on the conclusiongiven above the principles to set the threshold of the SLB system are concluded. Itsanti-jamming performance for different false targets is evaluated by computer simulates.In addition, a new algorithm for auxiliary antenna beam pattern shaping satisfied thesystem is proposed based on antenna elements choosing.Secondly，the influencing factors about SLC system performance are discussed, andthe influence of array elements coincide on cancellation ratio is showed by simulations. Inaddition, analyzed the performance of SLB and SLC system’s by countering thesinusoidal weighted frequency modulation jamming.Thirdly， analyzed the influence of angle gird division and power allocation to agiven widen nulling algorithm when the jamming perturbation existed, and a newalgorithm with deeper widen nulling but less angle grid division is proposed.Fourthly， to deal with the elevated sidelobe level and steering vector mismatchsensitivity of traditional capon beamforming, we introduce the segmented constraint and sparse constraint into the capon beam pattern shaping model, and propose modifiedsegmented constraint models of minimizing the ratio of sidelobe and mainlobe array gain.The new models of segmented sparse constraint and suppression are proposed andverified to be with a higher output SINR and lower sidelobe level. Furthermore， theimprovment of robustness and faster convergences have been given by introducing thesidelobe suppression into the eclipse restriction. Finally，analyzed the PO nullingalgorithms based on the SVD-PO algorithms in transmit arrays.Lastly， based on the GUI platform of MATLAB, the flow design and moduleconstruction of MMW-AESA radar anti-jamming simulation system are completed.