Clutter Analysis And Research On Clutter Suppression Method Under Non Ideal Condition For Moving Radar

As the modern warfare is developing towards informatization and networking,airborne radar has become the core equipment for the early warning aircraft and battlefield surveillance aircraft to get the battlefield information.However,the airborne radar will be seriously affected by the clutter when it works,the ground clutter has wide distribution and high intensity;at the same time due to the movement of the carrier aircraft,the clutter spectrum is greatly broadened,so the target is often submerged in the clutter.Space time adaptive processing(STAP)technology can effectively suppress clutter and improve the target detection performance of airborne radar.In order to improve the performance of the system,this thesis studies the clutter's characteristics and its suppression methods of conventional planar array airborne radar and cylindrical conformal array airborne radar.For the conventional planar array airborne radar,an adaptive Doppler angle compensation algorithm based on iterative adaptive algorithm is proposed,which can effectively improve the performance of the conventional adaptive angle Doppler compensation algorithm;For the cylindrical conformal array airborne radar,an improved adaptive algorithm based on iterative adaptive registration is proposed,which can effectively complete the compensation of conformal airborne radar's clutter range dependency.The main contents of this thesis are summarized as follows:1.The clutter model of the conventional planar array radar is studied,and the space-time processing method of clutter suppression is discussed.Based on the description of the equal Doppler line and the equal cone angle line of the airborne radar,this thesis analyzes the reason why the clutter possesses the range dependency.We systematically analyze the angle Doppler characteristics and range Doppler characteristics of the airborne radar clutter in the presence of different array configurations,and on this basis,this thesis makes a brief analysis of the space time processing technology and the reduced dimension space-time processing technology.The simulation results verify the effectiveness of the STAP technology.2.The range-dependency of the conventional planar array airborne radar clutter is studied.Aiming at the nonuniformity of training sample data caused by the clutter's range-dependency of conventional planar array airborne radar,an iterative adaptive angle Doppler compensation algorithm is proposed.The algorithm determine the center position of mainlobe clutter spectrum of training samples by an adaptive iterative method,and then a two-dimensional compensation of the spatial domain and Doppler domain is carried out by using the angle Doppler compensation algorithm to obtain the training sample data which is consistent with the statistical characteristics of the cell under test,and then uses them to form the clutter covariance matrix,and calculates the filter weight vector,so the nonhomogeneous clutter can be effectively suppressed.3.The clutter model of the cylindrical collinear array airborne radar and the cylindrical collinear array airborne radar clutter suppression method are studied.Based on the analysis of the conformal array airborne radar's clutter characteristics,an improved adaptive algorithm based on iterative adaptive registration is proposed.The method reconstructs the clutter data in three-dimensional space by iterative adaptive processing,and solves the transformation matrix by reconstructing the covariance matrix of the range gate data,and uses the transformation matrix to register the data of the training range gate to the reference range gate data in order to complete the compensation of the clutter's range dependency.