Underwater DOA Estimation Based On The Arbitrary Intersecting Uniform Line Array With Unknown Acoustic Velocity

Direction of arrival(DOA)estimation is a very important research direction in array signal processing.With the strategic goal of building a maritime power in China,underwater DOA estimation is particularly important,and it plays an important role in underwater military reconnaissance,positioning and tracking,signal detection,sea operation and marine resources development.DOA estimation algorithm using wave path difference between the signals on the receiving array to estimate the azimuth information of the signal space,but the wave path difference is related to the wave propagation velocity and the water is a variable velocity environment,so the acoustic velocity has a great influence on the accuracy of the underwater DOA estimation algorithm and it is necessary to learn how to eliminate the influence of acoustic velocity factor on the performance of underwater DOA estimation under variable velocity environment.In this paper,an underwater DOA estimation algorithm,which can eliminate the influence of the acoustic velocity factor,is studied in this paper.The specific contents are summarized as follows:1.The theoretical basis of DOA estimation is expounded.The structure of spatial spectrum estimation system,one-dimensional and two-dimensional DOA estimation principles,commonly used arrays and mathematical models are briefly introduced,and the corresponding DOA estimation performance indicators are given.Else,the principle of one-dimensional and two-dimensional DOA estimation based on the conventional ESPRIT algorithm and the influence of the unknown acoustic velocity on their estimation performance are also introduced.What's more,the existing underwater DOA estimation algorithm with unknown acoustic velocity is given.2.Simulation of one-dimensional and two-dimensional DOA estimation based on conventional ESPRIT algorithm is carried out with unknown acoustic velocity,and the influence of unknown acoustic velocity on the performance of conventional estimation is analyzed by simulation experiments.3.According to the influence of unknown acoustic velocity on the performance of conventional one-dimensional DOA estimation,a one-dimensional DOA estimation algorithm based on adjustable angle uniform linear array is proposed,this algorithm can make full use of the plane geometry relationship between uniform linear array and eliminate the influence of acoustic velocity factor on the estimation performance of one-dimensional direction angle.The simulation experiment results show that the proposed algorithm in this paper is superior to the conventional one-dimensional DOA estimation algorithm and the existing relatedone-dimensional algorithm in estimation performance with unknown acoustic velocity.4.According to the influence of unknown acoustic velocity on the performance of conventional two-dimensional DOA estimation,a two-dimensional DOA estimation algorithm based on adjustable angle uniform linear array is proposed,this algorithm can make full use of the stereoscopic geometry relationship between uniform linear array and eliminate the influence of acoustic velocity factor on the estimation performance of pitch angle.The simulation experiment results the proposed algorithm is superior to the conventional two-dimensional DOA estimation algorithm and the existing related two-dimensional algorithm in estimation performance of pitch angle with unknown acoustic velocity.