Wideband Direction Finding Method Based On Conpressed Sensing

In recent years,with the development of communication technology,wideband signals have become more and more widely used in various fields.The previous DOA estimation techniques for narrowband signals are no longer suitable for wideband signal DOA estimation.Therefore,a mature and applicable wideband signal DOA has been developed.It is estimated that technology has become the primary task of contemporary scholars.Tr aditional sampling techniques need to satisfy Nyquist's theorem.Compared with broadband signals,if the sampling process is to be completed,a large amount of data needs to be taken.A too high sampling rate will inevitably produce a large amount of original sampling data,which will bring huge pressure to the transmission,storage and processing of information,which imposes great pressure on sampling technology and hardware.The equipment has put forward relatively high requirements,so that it is difficult to achieve in real life.Compressed sensing theory,as an emerging science and technology,breaks through the limitations of Nyquist theorem.After nearly ten years of development,many scholars have successfully applied compressed sensing theory to DOA estimation technology,and constructed a series of DOA estimation methods based on compressed sensing.This article mainly focuses on the in-depth study of the problems in the wideband DOA estimation method based on compressed sensing.For example,the compressed sensing theory needs to grid mismatch problems caused by gridding the estimated angle range,which increases the estimation error;Sparse Bayesian theory is used to solve the posterior probability density function,which has the disadvantages of complicated solving process,large amount of calculation and easy to fall into local optimal solution.The DOA estimation of wideband signal under impulsive noise environment,due to the absence of second-order moments and high-order variables in its noise characteristics,traditional direction finding methods cannot handle it.In response to these existing problems,and based on the constructed mathematical model,the objective function is converted into an extreme value optimization model,and then a ne w intelligent optimization algorithm is designed to solve these problems and improve the performance of the compressed sensing-based broadband DOA estimation method1.Aiming at the grid mismatch problem in the wideband DOA estimation method based on compressed sensing,first reduce the estimation error by Taylor expansion,supplement the estimated angle that does not fall in the correct grid,and then use the quantum charged system algorithm to its target The function is optimized for solving.Compared with the traditional wideband DOA estimation method,this method has the advantages of strong global searc h ability,fast convergence speed,and high estimation success probability and estimation accuracy in the case of low signal-to-noise ratio.2.Aiming at the complicated solution process in sparse Bayesian theory,large amount of calculation,and easy to fall into local optimal solutions,a quantum cat swarm algorithm is designed to solve the problems.The unique search mode and tracking mode of the quantum cat swarm algorithm enable it to have stronger global search capabilities,which can quickly find the global optimal solution and avoid falling into the local optimal solution.The black box processing method of the intelligent optimization algorithm can avoid the tedious formula derivation process,shorten the running time,and accelerate the convergence speed.3.For the wideband signal DOA estimation under impulsive noise environment,there are no second-order moments and high-order variables.Using fractional low-order moments for processing can more effectively suppress the impact of impulsive noise on the estimation results and reduce estimation errors.The quantum dragonfly algorithm is used to optimize the objective function,which can effectively avoid the redundant calculation and estimation errors caused by the eigen decomposition of the covariance matrix.It makes the DOA estimation of wideband signal under impact noise environment have higher estimation accuracy and estimation success probability.