Research On Adaptive Mainlobe Interference Suppression Algorithm Of Array Radar

Adaptive beamforming, which is able to enhance the desired signal while suppressingthe interferences without any prior information of the interferences, has wide applicationsin radar, sonar, medical imaging, radio astronomy, and other fields. It is well known theperformance of the traditional adaptive beamforming algorithms degrades significantlywhen the interference is located in mainlobe, so the research on the adaptive mainlobeinterference suppression algorithm allows of no delay.Firstly, the basis of the adaptive beamforming, which supplies signal model for the fullpaper, is introduced. Besides the introduction of the array model and the adaptivebeamforming principles, this part also discusses the problems of adaptive beamforming atsub-array level. In phased array radar in which the array usually comprises hundreds evento thousands of elements, if the adaptive weight vector is computed directly usingtraditional methods, the computation complexity is very high. So in practice, sub-arrayconfiguration is usually adopted. Thus we need to adopt ADBF at sub-array level. Then animproved adaptive beamforming algorithm at sub-array level based on interferencesubspace and penalty function is proposed, which is able to suppress the interferenceseffectively.Secondly, when ground-based radar is applied to the detection of long-range targets,the interference around the target is located primarily in the radar mainlobe, such that theradar detection capabilities are significantly. In this part, the adaptive beamforming basedon auxiliary array is discussed and applied to process the radar echo data which contains themainlobe interference. Simulation results demonstrate the superiority of the algorithm.When the interference is located in mainlobe, the traditional adaptive beamformingwill form a null in mainlobe to suppress the interference, which leads to the deterioration ofthe adaptive beamforming performance. In order to overcome these shortcomings, theblocking matrix preprocessing (BMP) based algorithm and eigen-projection matrixpreprocessing (EMP) based algorithm are firstly discussed, and then a mainlobeinterference suppression method is proposed based on eigen-projection processing andcovariance matrix reconstruction, which can effectively suppress all interferences including the mainlobe interference.Lastly, an experiment of phased array radar is constructed based on the above researchon the adaptive beamforming. The collected experimental data is applied to analyze theperformance of the proposed adaptive mainlobe interference suppression algorithm.