Research On Direction Finding And Ambiguity Solving Methods And Array Calibration Technique

In radar direction finding systems, interferometer method has high stability and is easyto realize, so it is widely used in estimation of direction of arrival. To solve the problemswhich influence the performance of direction finding and ambiguity solving, mainlyanalyzing the ambiguity solving methods and array calibration techniques. Improvedalgorithm is proposed, the model of array errors is established, and reasonable calibrationmethod is applied. The experiment in actual direction finding system has also testified thevalidity of the method.Contradiction between accuracy and fuzzy multivalued of interferometer method isanalyzed. The common direction finding methods are expounded and compared, the model ofnonuniform circular antenna array is established, the method is improved based on theanalysis of the factors which influence the errors in the process of calculating, which providestheoretical basis for taking full advantage of antenna space and establishing more flexiblemodel of array, the simulation results verify the validity of the method, and the influence onthe ambiguity solving performance of different antenna apertures is compared.The signal model is established based on the factors and definitions of array errors. Theinfluences of array errors on accuracy and ambiguity solving performance are analyzed,which verify the necessity of array calibration to improve direction finding performance.In order to solve the problems of the array errors, typical array calibration techniques arestudied and compared in their algorithm and implementation. According to the actualconditions of the system, the method of self calibration based on multidimensional iterative isselected, which is analyzed specifically and the results is applied to compensate array errors.The relationship between the parameters of the iterative is analyzed through simulation, theresults verify the improvement of direction finding performance through array calibrating.According to the nonuniform circular antenna array of actual system, measured data iscollected. Based on the improved method, the applicative model of mutual coupling errors isestablished, self calibration is applied to compensate the errors, the simulation results verifythe improvement of system performance through improved algorithm and array calibration.