DOA Estimation Based On Compressed Sensing And Its FPGA Implementation

The Direction of Arrival(DOA)estimation is a popular research direction in the field of array signal processing and is widely used in engineering.The traditional DOA estimation methods have certain limitations and can no longer meet the current needs of signal processing.In recent years,the development of compressed sensing theory has provided new directions for sparse signal processing.It improves the efficiency of sparse signal processing.The sparse characteristics of the spatial signal combine with the theory of compressed sensing,resulting in new DOA estimation methods.Compared with traditional DOA estimation methods,DOA estimation algorithms based on compressed sensing have the advantages of single snapshot and decoherence,which have important research significance and application value.This paper first studies the basic theory of DOA estimation of array signals and compressive sensing,discusses the DOA estimation model based on compressed sensing theory framework,and analyzes the advantages of its single snapshot and decoherence.Because greedy algorithms have the advantages of simple calculation and high reconstruction accuracy,this paper mainly discusses the compressed sensing greedy reconstruction DOA estimation algorithms.The paper researches DOA estimation effects of Orthogonal Matching Pursuit(OMP)algorithm,Regularized Orthogonal Matching Pursuit(ROMP)algorithm,Compressive Sampling Matching Pursuit(CoSaMP)algorithm and Subspace Pursuit(SP)algorithm in aspects such as number of array elements and noise immunity.Then the paper explores the performance of the algorithms in the case of a small angular interval of the incident signal.Simulation results show that the OMP algorithm is less sensitive to the number of elements and has better noise immunity.However,in the case of similar arrival angles,the estimated accuracy rate still needs to be improved.For the lack of resolution of OMP algorithm,this paper first introduces a new greedy algorithm—Multipath Matching Pursuit(MMP)algorithm—in DOA estimation,which effectively improves the reconstruction accuracy.However,due to the high computational complexity of the MMP algorithm,this paper proposes an improved MMP(ANSN-MMP)algorithm based on the adaptive search number of the tree nodes.Simulation experiments verify the improvement of DOA estimation angle resolution by MMP and ANSN-MMP algorithms.Compared with the MMP algorithm,the ANSN-MMP algorithm improves the efficiency of the algorithm under the premise of ensuring the estimation accuracy,and more satisfies the real-time processing conditions.Finally,the overall design of FPGA based on ANSN-MMP algorithm DOA estimation is studied.According to the flow of the algorithm,the paper designs the sensing matrix storage module,the residual storage module,the complex product module,the inner product comparison module,the residual update module,the residual comparison and angle output module,etc.And it studies a matrix inversion algorithm that is easy to implement in hardware.Then the entire system is implemented under the control of the system clock.The final output estimated value is close to the set angle of incident signal,which verifies the correctness of the overall design.