Research On Clutter Suppression And DOA Estimation Of Airborne 3D Heterogeneous Array

The airborne three-dimensional heterogeneous array is a three-dimensional complex array composed of multiple curved arrays arranged on the fuselage.It has a good aerodynamic shape,stealth ability,and can achieve 360° coverage of the beam,which can meet the needs of target detection in a complex battlefield environment,so it has gradually become a new direction of research at home and abroad.However,the complex array configuration of the airborne three-dimensional heterogeneous array results in very complex signal clutter characteristics and target characteristics,making the corresponding clutter suppression and target detection more difficult.This paper focuses on the research on clutter suppression and DOA estimation methods of airborne three-dimensional heterogeneous arrays.The main research contents are as follows:1.Aiming at the problem that the element radiation pattern of the airborne three-dimensional heterogeneous array does not satisfy the pattern product theorem,a method for solving the polarization pattern based on Euler’s rotation transformation is given.The transformation from the local pattern to the global pattern is completed by Euler rotation transformation.Then referring to the form of the space-time guided vector clutter model of the linear array,combined with the special geometric configuration of the airborne three-dimensional heterogeneous array,the space-time-polarization clutter modeling of the heterogeneous array is completed.2.Aiming at the problems of high cost and massive data processing caused by the large number of elements of the airborne three-dimensional heterogeneous array,two sparse array design methods are given.The simulation shows that the two methods can optimize the antenna pattern while reducing the number of array elements.3.Aiming at the problem that conventional clutter suppression methods are not suitable for airborne three-dimensional heterogeneous arrays,a clutter suppression method based on blind source separation and a clutter suppression method based on sparse STAP are proposed.The former uses the difference in the statistical characteristics of the amplitude distribution between clutter and target,realizes the separation of clutter and signal through blind source separation algorithm.At the same time,the simulation analysis shows that the method also has good anti-interference ability..The latter is based on the space-time-polarization model of the airborne three-dimensional heterogeneous array given in the first part,introduces the sparse STAP theory,constructs a clutter spectrum sparse recovery model of the airborne three-dimensional heterogeneous array,and proposes a message based on complex approximation The transmitted sparse STAP method realizes the suppression of clutter.The simulation verifies that the two methods have good clutter suppression performance.4.Aiming at the problem that conventional DOA estimation methods cannot be applied to airborne three-dimensional heterogeneous arrays,an airborne three-dimensional heterogeneous array DOA estimation method based on compressed sensing is proposed.By analyzing the particularity of the airborne three-dimensional heterogeneous array array signal,the array manifold model of the signal is obtained by Euler rotation transformation,and then the compressed sensing model is constructed,and two algorithms for solving the sparse reconstruction problem are proposed.Finally,aiming at the grid mismatch problem in the compressed sensing model,a grid mismatch correction method based on constrained total least squares is presented.The simulation processing results verify the feasibility and effectiveness of the DOA estimation method and grid mismatch correction method proposed in this paper.