Array Diagnosis Method In Non-ideal Environment

Antenna arrays have been widely used in real applications.To achieve high array gain and high spatial resolution,arrays with a large number of elements become more and more popular.Large number of elements causes increase of the probability of array elements failure.The failing elements bring unexpected effect on the performance of the array,Therefore,it is important to locate the failing elements which is the purpose of array diagnosis.And in real life radio frequency environment,impulsive noise may exist due to natural bursts like lightening and man-made interferences.Array diagnosis method in the impulsive noise environment is proposed.Two main aspects are included:1.In real applications,phase measuring is expensive.Therefore,array diagnosis methods using amplitude-only field data appear.Therefore,an array diagnosis method using amplitude-only far field data in impulsive noise environment is proposed.For amplitude-only far field data,power of the observed field is quadratic with respect to array excitation,which leads to a nonlinear inverse problem to restore array excitation.Such a nonlinear inverse problem is transformed to a linear inverse problem,where array excitation vector is replaced by a lifted vector.Based on the structure of the lifted vector,an absolute array excitation vector which has identical structure to that of array excitation vector is defined.Since these two vectors share the same structure,it is assumed that they also share the same kind of probability distribution.Specifically,generalized Gaussian distribution with different parameters to address different element failing rates is used to model the probability distribution of the real array excitation vector and the absolute array excitation vector.To model the impulsive noise,Laplacian probability distribution function is used.The Maximum a Posterior?MAP?criterion is adopted to formulate the optimization problem which is eventually found to be convex.However,this convex optimization problem does not have an analytical solution.To solve it,proximal gradient method is applied,which yields an iterative update algorithm.Finally,computer simulations and experiment are conducted to verify validity and superiority of the proposed method.2.In this paper,an array diagnosis method in the presence of array mismatch and impulsive noise environment is proposed.In the case of array mismatch,there will be corresponding errors in array manifold of the array under test.In addition,taking into account the mixed noise present in the actual environment.Conventional array diagnosis methods based on compressive sensing cannot achieve the desired effect.In order to solve this problem,an array diagnosis method based on impulse noise environment is proposed with full consideration of array error.Based on the far-field data model of the antenna array,the mathematical model corresponding to the proposed problem is obtained.The₁l-norm constraint is applied to the impulseive noise.After derivation,a new optimization problem is obtained and solved.Finally,the proposed method is validated by computer simulation.