Research On The DOA Of Coherent Signals Based On The MUSIC Algorithm

The direction of arrival of coherent signal is an important research in array signal processing. Based on the study and research of the existing DOA estimation algorithm in this paper, the parimary study and innovation of the article are as follows:First, this paper describes the traditional signal DOA estimation algorithm,including delayed-add method, Capon method and the MUSIC algorithm. The computer simulation results indicate that MUSIC algorithm has a high precision and a good resolution, however, the MUSIC algorithm has a serious decline of the performance of estimation under the condition of the coherent signal source.Secondly, aiming at the shortcomings of MUSIC algorithm, this paper introduces a decorrelation algorithms commonly based on dimensionality reduction algorithms-spatial smoothing algorithm, including forward spatial smoothing algorithm, backward spatial smoothing algorithm and forwaed/backward spatial smoothing algorithm. Spatial smoothing algorithm can accurately estimate the DOA of coherent sources, but at the expense of the number of array elements, and the estimation performance of non-coherent sources is declined, while also increasing the amount of computation.Further improvement of the research results come forth continuously, one of the typical algorithm is IMUISC algorithm, the essence of the IMUSIC algorithm is the number of subarray equaled with the total number of array element about the spatial smoothing algorithm. As can be seen from the simulation results, IMUSIC algorithm overcomes the above shortcomings, having a good resolution of the coherent and non-coherent sources. But in the case of low SNR, the estimation performance of IMUSIC algorithm will seriously deteriorate.Finally, aiming at the problems of the IMUSIC algorithm, this paper constructs a MUSIC estimation algorithm based on the eigenspace, which is called the EMUSIC algorithm for short, different from the MUSIC algorithm and the IMUSIC algorithm only using the noise subspace, EMUSIC algorithm takes advantage of the signal subspace and noise subspace characteristics. According to the result of simulation, the EMUSIC algorithm of DOA estimation performance is better than MUSIC algorithm in the non-coherent case, better than the IMUSIC algorithm in the coherent case, and thealgorithm in the condition of low SNR still have a good resolution, so the EMUISC algorithm is an excellent method.