Clutter Characteristics Analysis And Research On Space-domain Reduced-rank Method Under Non Ideal State For Moving Radar

In order to meet the needs of war,radar is often installed on various special platforms such as large special aircraft,fighter jets,missiles,to help weapons and equipment obtain a wider field of view,stronger low-altitude target detection and better tracking capabilities.The radars that installed on the aerial platform are unavoidably affected by ground clutter.Clutter suppression has always been a key technical issue in the research and development of this type of radar.Space time adaptive processing(STAP)technology can suppress clutter effectively and improve the performance of motion target detection.However,the current research is focused on the ideal situation,that the aerial platform flies ideally and the axis of the radar array is parallel to the ground.There are few studies on the situation that the nonideal flight of aerial platform and the more general placement of the radar array.When the motion state of the aerial platform and the placement state of the radar array are different,the characteristics of clutter will also be different.The performance of the clutter suppression method for the ideal situation will be reduced,which is difficult to meet the requirements of war.Therefore,for different motion states of the aerial platform and for different placement states of the radar array,it is very significant to carry out the research about the space-time characteristics and the suppression methods of clutter.This thesis studies the characteristics and suppression method of clutter,which caused by no-ideal motion state of aerial radar,based on new clutter model that established in this thesis.Aiming at the problem of poor main-lobe clutter suppression performance in the case of conventional subarray division when the array placement state is non-ideal,this thesis gives two new subarray division methods,which can improve clutter suppression performance.The main works of this thesis are summarized as follows:1.Research on the clutter characteristics of ideal airborne radar,and STAP method.First,an ideal airborne radar clutter model is established,and systematically analyzes the ideal airborne radar clutter characteristics as a comparison object for subsequent non-ideal motion radar clutter characteristics.Then introduced the basic principle of STAP and several common STAP methods.2.Research on the modeling and characteristics of clutter,of which the motion state is non-ideal.Aiming at the different motion states of the aerial platform and the different radar array placement states,this thesis studies the characteristics of the motion radar clutter more generally,and establishes a unified motion radar clutter model.This thesis systematically analyzes the clutter characteristics of non-ideal motion radars,and summarizes them.Clarifies the impact of the changes in the motion state of the aerial platform and the placement of the radar array on the clutter characteristics.3.Research on the method of dimensionality reduction in space domain.Aiming at the problem of poor main-lobe clutter suppression performance when the conventional sub-array division method is placed in a non-ideal array,two new sub-array division methods are proposed in this thesis.The first method is to divide a small subarray at the four vertices of the rectangular array,destroying the two-dimensional separable characteristics of the subarray division.The second method distributes the airspace degrees of freedom more to the horizontal dimension,improves the utilization of the system airspace degrees of freedom,and thus improves the clutter suppression performance.Finally,the performance of the two subarray division methods and the conventional sub-array division method are compared,and analyzed through simulation experiments.The effectiveness of the proposed method is verified.