Study On The DOA Estimation Of Wideband Array Signals

Array signal processing technology is widely used in many areas,and it has a significant development in the military and national economy.As an important branch of array signal processing,Direction of Arrival(DOA for short)has become a hot research topic.The research of DOA estimation algorithm for narrowband signals is already mature.However,traditional algorithms for narrowband signals are not suitable for broadband signals which have more effective information and higher application value.Nowadays,the research of high-resolution DOA estimation algorithm of wideband signals is still in the development stage and needs to be further improved.This paper focuses on the high-resolution DOA estimation algorithms for wideband signals.The research contents are as follows:1.The idealized assumption of the array of sensors is used to construct the signal model for wideband and narrowband signals respectively.Besides,the classical narrowband high-resolution detection algorithms are studied,and the influence of various parameters of array signal model on the estimation accuracy of MUSIC and ESPRIT algorithm is analyzed by experiment simulation.2.Analyze the upper limit of the number of sources that can be achieved when the signals are coherent by the spatial smoothing technique,and study the modified MUSIC algorithm which is based on matrix conjugate reconstruction to realize decoherence.The simulation result shows the performance of three algorithms,such as forward spatial smoothing,for-backward spatial smoothing ana modified MUSIC.3.the inconerent Signai-Subspace Method(ISM for short)for wideband signal processing is analyzed,and the modified ISM which is based on modified MUSIC algorithm is used to estimate the DOA of coherent signals.In view of the construction of the focusing matrix of Coherent Signal-Subspace Method(CSM for short)is not unique,RSS algorithm which is based on array manifold and TCT algorithm which is based on the data received by array after denoising are studied,and experiment simulation compares the performance of two algorithms under different signal-to-noise ratio.4.The statistical performance of traditional MUSIC algorithm has mainly been characterized in the case where the number of snapshots converges to positive infinity while the number of antennas remains fixed.The corresponding conclusion is valid only when the number of snapshots is much larger than that of antennas in finite sample size.However,the number of snapshots is limited in practical application.When both the number of antennas and that of snapshots converge to positive infinity,the MUSIC algorithm will asymptotically biased.In this paper,an improved MUSIC algorithm is proposed to improve accuracy of DOA estimation in the case of limited number of samples.The improved algorithm is adopted in the narrowband model data of frequency domain after using CSM to focus the array manifold,and the simulation result shows that the improved CSM has higher estimation accuracy.