Study On Dimension-Reduced Space-Time Adaptive Processing Approaches For Airborne Radar

With the continuous development of science and technology and various equipment,there is more and more higher requirement to radar for contemporary war.The airborne phased array radar is widely concerned by researchers thanks to its special advantages,but when it operates at look-down mode,it will be significantly affected by the ground clutter,and clutter suppression becomes arduous because of several effects consist of clutter spectral spreading in the doppler domain and heterogeneity in the range due to the motion of platform and extraneous environment.Space-Time Adaptive Processing(STAP)is a kind of the two dimensional adaptive filter with joint spatial and temporal domain to realize clutter suppression and interferences suppression,which can suppress ground clutter effectively and improve the detection performance of moving target greatly.Although full dimension STAP exhibits excellent performance,it is hard to apply in practice that is because the enough secondary samples that superhigh freedom degree of system brings are tremendous.In addition,the computational complexity of implementation of fully STAP can’t be accepted too.Therefore,the study on dimension-reduced STAP approaches for airborne radar is of great significance.The design of reduced configuration based on auxiliary channel processing and rank reduction within element domain are widely concerned in this dissertation,and this thesis puts forward three simplified auxiliary channel algorithms and a subarray division method based on differential evolution algorithm.The main contents of this thesis can be organized as follows:1.The research on the characteristics of the ground clutter and STAP algorithms.First,the echo signal model of the airborne phased array radar is established,and the characteristics of the ground clutter are analyzed detailedly from three domains including: the doppler characteristic,the angle-doppler characteristic and the range-doppler characteristic.Then it introduces the basic principles of STAP and the problems in its pratical application.Finally,the simulation experiments and comparative analysis of several commonly used reduced-dimension algorithms are described.2.The research on the method of reducing STAP based on auxiliary channel method.The performance of the auxiliary channel method will be declined sharply when there are array amplitude and phase errors,and the algorithm is hardly applied in the large phased array radar.In order to solve the two problems,three simplified auxiliary channel algorithms are put forward in this thesis,and the simulation experiment results give a comparative analysis of performance between the proposed algorithm and the original auxiliary channel algorithm,which is used to verify the effectiveness.3.The research on the reduced-dimension within element domain.Beacuse the large phased array radar has a lot of elements,the need for dimensionality reduction in element domain is must.Firstly,the theory of subarray division of phased-array antenna and the common subarray division method are introduced,and the principle of subarray division is summarized.Then,on account of the principle of subarray division,a subarray division method based on differential evolution algorithm is proposed.Finally,the simulation experiments prove that the method can quickly and accurately obtain the optimal subarray partition.