Study On Space-time Adaptive Processing For Airborne Frequency Diverse Array Radar

An important function of the radar system is to detect the moving targets.The airborne radar has great advantages in detecting the ground and the low altitude flight targets.Under the strong clutter background,the space-time adaptive processing combined with the two-dimensional information of space-time,the surface clutter can be effectively suppressed,and the ground targets can be continuous be detected and monitored.Airborne radar with frequency diversity array introduces a new array system.The addition of frequency increment provides additional distance dimensionality for radar detection,which can effectively solve the distance blur and realize the separation of interference and real target.Frequency diversity array radar in the space-time adaptive processing,on the one hand,has to face a huge amount of computing and storage problems,on the other hand,due to the continuous development of radar technology,the radar resolution continues to increase,and the target signal will inevitably enter to the training sample,resulting in the phenomenon of the target cancellation,while the motion target parameters are not accurate,resulting in the problems of model mismatch such as the target-oriented vector constraints are inaccurate.In this paper,we study various dimension reduction methods to alleviate the complex operations in space-time processing.Progressively,on the basis of the traditional robust adaptive method,we consider the further study of the improved robust space-time adaptive processing method.Frequency diversity radar is different from traditional phased array radar,and distance dependent compensation becomes a key part of space-time adaptive processing.In this paper,we discuss the solution of the distance dependence problem of frequency diversity radar,and continue to explore the spaceborne adaptive dimensionality reduction and robust processing method of frequency diversity radar.In view of the above complex operation,the engineering implementation is difficult,and the the problem of target pollution training samples caused by the multi-objective and high-resolution target expansion of the scene,and the guidance vector mismatch caused by incomplete array error correction and inaccurate estimation of the motion parameter.This paper is first based on the study of FDA launch and reception,then the characteristics of the radar radar clutter distribution were studied and the distance dependence compensation was made.And then from two aspects of the problem started to study: First,introduced three kinds of classic fixed structure dimensionality reduction method,i.e.the auxiliary channel(ACR),Doppler channel joint processing(m DT),Local Joint processing(JDL).The construction of the dimensionality reduction matrix is given.Combining these three dimensionality reduction methods with the frequency diversity array radar,the frequency diversity radar space-time adaptive dimensionality reduction achieved.Greatly reducing the amount of calculation,achieves the quasi-optimal output performance.Second,the two-dimensional processing model of frequency diversity radar is constructed.A brief introduction of the principle and lack to the diagonal loading,based on the worst case performance optimization,linear constraint minimum variance method.An improved LCMV robust beamforming method is proposed.By comparing the above three kinds of robust processing methods and the improved method,It is verified that the improved LCMV robust beamforming method still has good robustness in the presence of array error,parameter estimation error and steering vector mismatch.